23. Octo-SPI interface (OCTOSPI)

23.1 OCTOSPI introduction

The OCTOSPI supports most external serial memories such as serial PSRAMs, serial NAND and serial NOR flash memories, HyperRAM™ and HyperFlash™ memories, with the following functional modes:

• • indirect mode: all the operations are performed using the OCTOSPI registers to preset commands, addresses, data, and transfer parameters.
• • automatic status-polling mode: the external memory status register is periodically read and an interrupt can be generated in case of flag setting. This feature is only available in regular-command protocol.
• • memory-mapped mode: the external memory is memory mapped and it is seen by the system as if it was an internal memory, supporting both read and write operations.

The OCTOSPI supports the following protocols with associated frame formats:

• • the regular-command frame format with the command, address, alternate byte, dummy cycles, and data phase
• • the HyperBus™ frame format

23.2 OCTOSPI main features

• • Functional modes: indirect, automatic status-polling, and memory-mapped
• • Read and write support in memory-mapped mode
• • External (P)SRAM memory support
• • Support for single, dual, quad, and octal communication
• • Dual memory configuration, where eight bits can be sent/received simultaneously by accessing two quad memories in parallel
• • SDR (single-data rate) and DTR (double-transfer rate) support
• • Data strobe support
• • Fully programmable opcode
• • Fully programmable frame format
• • Support wrapped-type access to memory in read direction
• • HyperBus support
• • Integrated FIFO for reception and transmission
• • Asynchronous bus clock versus kernel clock support
• • 8-, 16-, and 32-bit data accesses allowed
• • DMA protocol support
• • DMA channel for indirect mode operations
• • Interrupt generation on FIFO threshold, timeout, operation complete, and access error
• • AHB interface with transaction acceptance limited to one: the interface accepts the next transfer on AHB bus only once the previous is completed on memory side.

23.3 OCTOSPI implementation

Table 215. OCTOSPI implementation

23.4 OCTOSPI functional description

23.4.1 OCTOSPI block diagram

Figure 139. OCTOSPI block diagram in octal configuration

Figure 140. OCTOSPI block diagram in quad configuration

Figure 141. OCTOSPI block diagram in dual-quad configuration

23.4.2 OCTOSPI pins and internal signals

Table 216. OCTOSPI input/output pins

Caution: Use the same configuration (output speed, HSLV ^(a) ) for all OCTOSPI input/output pins to avoid any data corruption.

Table 217. OCTOSPI internal signals

a. When applicable.

23.4.3 OCTOSPI interface to memory modes

The OCTOSPI supports the following protocols:

• • regular-command protocol
• • HyperBus protocol

The OCTOSPI uses from 6 to 12 signals to interface with a memory, depending on the functional mode:

• • NCS: chip-select
• • CLK: communication clock
• • NCLK: inverted clock used only in the 1.8 V HyperBus protocol
• • DQS: data strobe used only in regular-command protocol as input only
• • IO[3:0]: data bus LSB
• • IO[7:4]:
  • – data bus MSB used in dual-quad and octal configurations
  • – data bus can be used as possible remap for quad-SPI mode

23.4.4 OCTOSPI regular-command protocol

When in regular-command protocol, the OCTOSPI communicates with the external device using commands. Each command can include the following phases:

• • Instruction phase
• • Address phase
• • Alternate-byte phase
• • Dummy-cycle phase
• • Data phase

Any of these phases can be configured to be skipped but, in case of single-phase command, the only use case supported is instruction-phase-only.

The NCS falls before the start of each command and rises again after each command finishes.

In memory-mapped mode, both read and write operations are supported: as a consequence, some of the configuration registers are duplicated to specify write operations (read operations are configured using regular registers).

Figure 142. SDR read command in octal configuration

The specific regular-command protocol features are configured through the registers in the 0x0100-0x01FC offset range.

Instruction phase

During this phase, a 1- to 4-byte instruction is sent to the external device specifying the type of operation to be performed. The size of the instruction to be sent is configured by ISIZE[1:0] in OCTOSPI_CCR and the instruction is programmed in INSTRUCTION[31:0] of OCTOSPI_IR.

The instruction phase can optionally send:

• • 1 bit at a time (over IO0, SO single in single-SPI mode)
• • 2 bits at a time (over IO0/IO1 in dual-SPI mode)
• • 4 bits at a time (over IO0 to IO3 in quad-SPI mode)
• • 8 bits at a time (over IO0 to IO7 in octal-SPI mode)

This can be configured using IMODE[2:0] of OCTOSPI_CCR.

The instruction can be sent in DTR mode on each rising and falling edge of the clock, by setting IDTR in OCTOSPI_CCR.

When IMODE[2:0] = 000 in OCTOSPI_CCR, the instruction phase is skipped, and the command sequence starts with the address phase, if present.

In memory-mapped mode, the instruction used for the write operation is specified in OCTOSPI_WIR, and the instruction format is specified in OCTOSPI_WCCR. The instruction used for the read operation and the instruction format are specified in OCTOSPI_IR and OCTOSPI_CCR.

Address phase

In the address phase, 1 to 4 bytes are sent to the external device, to indicate the address of the operation. The number of address bytes to be sent is configured by ADSIZE[1:0] in OCTOSPI_CCR.

In indirect and automatic status-polling modes, the address bytes to be sent are specified by ADDRESS[31:0] in OCTOSPI_AR. In memory-mapped mode, the address is given directly via the AHB (from any master in the system).

The address phase can send:

• • 1 bit at a time (over IO0, SO single in single-SPI mode)
• • 2 bits at a time (over IO0/IO1 in dual-SPI mode)
• • 4 bits at a time (over IO0 to IO3 in quad-SPI mode)
• • 8 bits at a time (over IO0 to IO7 in octal-SPI mode)

This can be configured using ADMODE[2:0] in OCTOSPI_CCR.

The address can be sent in DTR mode (on each rising and falling edge of the clock) setting ADDTR in OCTOSPI_CCR.

When ADMODE[2:0] = 000, the address phase is skipped and the command sequence proceeds directly to the next phase, if any.

In memory-mapped mode, the address format for the write operation is specified in OCTOSPI_WCCR. The address format for the read operation is specified in OCTOSPI_CCR.

Alternate-byte phase

In the alternate-byte phase, 1 to 4 bytes are sent to the external device, generally to control the mode of operation. The number of alternate bytes to be sent is configured by ABSIZE[1:0] in OCTOSPI_CCR. The bytes to be sent are specified in OCTOSPI_ABR.

The alternate-byte phase can send:

• • 1 bit at a time (over IO0, SO single in single-SPI mode)
• • 2 bits at a time (over IO0/IO1 in dual-SPI mode)
• • 4 bits at a time (over IO0 to IO3 in quad-SPI mode)
• • 8 bits at a time (over IO0 to IO7 in octal-SPI mode)

This can be configured using ABMODE[2:0] in OCTOSPI_CCR.

The alternate bytes can be sent in DTR mode (on each rising and falling edge of the clock) setting ABDTR in OCTOSPI_CCR.

When ABMODE[2:0] = 000, the alternate-byte phase is skipped and the command sequence proceeds directly to the next phase, if any.

There may be times when only a single nibble needs to be sent during the alternate-byte phase rather than a full byte, such as when the dual-SPI mode is used and only two cycles are used for the alternate bytes.

In this case, the firmware can use the quad-SPI mode (ABMODE[2:0] = 011) and send a byte with bits 7 and 3 of ALTERNATE[31:0] set to 1 (keeping the IO3 line high), and bits 6 and 2 set to 0 (keeping the IO2 line low), in OCTOSPI_IR.

The upper two bits of the nibble to be sent are then placed in bits 5:4 of ALTERNATE[31:0] while the lower two bits are placed in bits 1:0. For example, if the nibble 2 (0010) is to be sent over IO0/IO1, then ALTERNATE[31:0] must be set to 0x8A (1000_1010).

In memory-mapped mode, the alternate bytes used for the write operation are specified in OCTOSPI_WABR, and the alternate byte format is specified in OCTOSPI_WCCR. The alternate bytes used for read operation and the alternate byte format are specified in OCTOSPI_ABR and OCTOSPI_CCR.

Dummy-cycle phase (memory latency)

In the dummy-cycle phase, 1 to 31 cycles are given without any data being sent or received, in order to give the external device, the time to prepare for the data phase when higher clock frequencies are used. The number of cycles given during this phase is specified by DCYC[4:0] in OCTOSPI_TCR. In both SDR and DTR modes, the duration is specified as a number of full CLK cycles.

When DCYC[4:0] = 00000, the dummy-cycle phase is skipped, and the command sequence proceeds directly to the data phase, if present.

In order to assure enough “turn-around” time for changing the data signals from the output mode to the input mode, there must be at least one dummy cycle when using the dual-SPI, the quad-SPI, or the octal-SPI mode, to receive data from the external device.

In memory-mapped mode, the dummy cycles for the write operations are specified in OCTOSPI_WTCR. The dummy cycles for the read operation are specified in OCTOSPI_TCR.

Data phase

During the data phase, any number of bytes can be sent to or received from the external device.

In indirect mode, the number of bytes to be sent/received is specified in OCTOSPI_DLR. In this mode, the data to be sent to the external device must be written to OCTOSPI_DR, while in indirect-read mode the data received from the external device is obtained by reading OCTOSPI_DR.

In automatic status-polling mode, the number of bytes to be received is specified in OCTOSPI_DLR, and the data received from the external device can be obtained by reading OCTOSPI_DR.

In memory-mapped mode, the data read or written, is sent or received directly over the AHB to the Cortex core or to a DMA.

The data phase can send/receive:

• • 1 bit at a time (over IO0/IO1 (SO/SI respectively) in single-SPI mode)
• • 2 bits at a time (over IO0/IO1 in dual-SPI mode)
• • 4 bits at a time (over IO0 to IO3 in quad-SPI mode)
• • 8 bits at a time (over IO0 to IO7 in octal-SPI mode)

This can be configured using DMODE[2:0] in OCTOSPI_CCR.

The data can be sent or received in DTR mode (on each rising and falling edge of the clock) setting DDTR in OCTOSPI_CCR.

When DMODE[2:0] = 000, the data phase is skipped, and the command sequence finishes immediately by raising the NCS. This configuration must be used only in indirect-write mode.

In memory-mapped mode, the data format for the write operation is specified in OCTOSPI_WCCR. The data format for the read operation is specified in OCTOSPI_CCR.

DQS use

The DQS signal can be used for data strobing during the read transactions when the device toggles the DQS aligned with the data.

The DQS management can be enabled by setting DQSE in OCTOSPI_CCR.

Figure 143. DTR read in octal-SPI mode with DQS (Macronix mode) example

23.4.5 OCTOSPI regular-command protocol signal interface

Single-SPI mode

The legacy SPI mode allows just a single bit to be sent/received serially. In this mode, the data is sent to the external device over the SO signal (Single-SPI Output) (whose I/Os are shared with IO0). The data received from the external device arrives via SI (Single-SPI Input) (whose I/Os are shared with IO1).

Compared to the SPI legacy mode, IO/SO and I1/SI are respectively equivalent to MOSI and MISO, having the OCTOSPI generating the clock.

The different phases can each be configured separately to use this single-SPI mode by setting to 001 the IMODE, ADMODE, ABMODE, and DMODE fields in OCTOSPI_CCR and OCTOSPI_WCCR.

In each phase configured in single-SPI mode:

• • IO0 (SO) is in output mode.
• • IO1 (SI) is in input mode (high impedance).
• • IO2 is in output mode and forced to 0 (to deactivate the “write protect” function).
• • IO3 is in output mode and forced to 1 (to deactivate the “hold” function).
• • IO4 to IO7 are in output mode and forced to 0.

This is the case even for the dummy phase if DMODE[2:0] = 001.

Dual-SPI mode

In dual-SPI mode, two bits are sent/received simultaneously over the IO0/IO1 signals.

The different phases can each be configured separately to use dual-SPI mode by setting to 010 the IMODE, ADMODE, ABMODE, and DMODE fields in OCTOSPI_CCR and OCTOSPI_WCCR.

In each phase configured in dual-SPI mode:

• • IO0/IO1 are at high-impedance (input) during the data phase for the read operations, and outputs in all other cases.
• • IO2 is in output mode and forced to 0.
• • IO3 is in output mode and forced to 1.
• • IO4 to IO7 are in output mode and forced to 0.

In the dummy phase when DMODE[2:0] = 010, IO0/IO1 are always high-impedance.

Quad-SPI mode

In quad-SPI mode, four bits are sent/received simultaneously over the IO0/IO1/IO2/IO3 signals.

The different phases can each be configured separately to use the quad-SPI mode by setting to 011 the IMODE, ADMODE, ABMODE, and DMODE fields in OCTOSPI_CCR and OCTOSPI_WCCR.

In each phase configured in quad-SPI mode:

• • IO0 to IO3 are all at high-impedance (inputs) during the data phase for the read operations, and outputs in all other cases.
• • IO4 to IO7 are in output mode and forced to 0.

In the dummy phase when DMODE[2:0] = 011, IO0 to IO3 are all high-impedance.

Octal-SPI mode

In regular octal-SPI mode, the eight bits are sent/received simultaneously over the IO[0:7] signals.

The different phases can each be configured separately to use the octal-SPI mode by setting to 100 the IMODE, ADMODE, ABMODE, and DMODE fields in OCTOSPI_CCR and OCTOSPI_WCCR.

In each phase that is configured in octal-SPI mode, IO[0:7] are all at high-impedance (input) during the data phase for read operations, and outputs in all other cases.

In the dummy phase when DMODE[2:0] = 100, IO[0:7] are all high-impedance.

Single-data rate (SDR) mode

By default, all the phases operate in SDR mode.

In this mode, when the OCTOSPI drives the IO0/SO, IO1 to IO7 signals, these signals transition only with the falling edge of CLK.

When receiving data in SDR mode, the OCTOSPI assumes that the external devices also send the data using CLK falling edge. By default (when SSHIFT = 0 in OCTOSPI_TCR), the signals are sampled using the following (rising) edge of CLK.

Figure 144. SDR write command in octo-SPI mode example

Note: Due to internal synchronization, up to six extra dummy clock cycles may be generated by the Octo-SPI interface after the last data is read.

Double-transfer rate (DTR) mode

Each of the instruction, address, alternate-byte, and data phases can be configured to operate in DTR mode setting IDTR, ADDTR, ABDTR, and DDTR in OCTOSPI_CCR.

In memory-mapped mode, the DTR mode for each phase of the write operations is specified in OCTOSPI_WCCR. The DTR mode for each phase of the read operations is specified in OCTOSPI_CCR.

In DTR mode, when the OCTOSPI drives the IO0/SO and IO1 to IO7 signals in the instruction, address, and alternate-byte phases, a bit is sent or received on each of the falling and rising edges of CLK.

When receiving data in DTR mode, the OCTOSPI assumes that the external devices also send the data using both CLK rising and falling edges. When DDTR = 1 in OCTOSPI_CCR, the software must clear SSHIFT in OCTOSPI_TCR. Thus, the signals are sampled one half of a CLK cycle later (on the following, opposite edge).

In DTR mode, it is recommended to set DHQC of OCTOSPI_TCR, to shift the outputs by a quarter of cycle and avoid holding issues on the memory side.

Note: DHQC must not be set when the prescaler value is 0, as this action leads to unpredictable behavior.

Figure 145. DTR write in octal-SPI mode (Macronix mode) example

Note: Due to internal synchronization, up to six extra dummy clock cycles may be generated by the Octo-SPI interface after the last data is read.

Dual-quad configuration

When DMM = 1 in OCTOSPI_CR, the OCTOSPI is in dual-memory configuration: if DMODE = 011, two external Quad-SPI devices (device A and device B) are used in order to send/receive eight bits (or 16 bits in DTR mode) every cycle, effectively doubling the throughput.

Each device (A or B) uses the same CLK and NCS signals, but each has separate IO0 to IO3 signals.

The dual-quad configuration can be used in conjunction with the single-SPI, dual-SPI, and quad-SPI modes, as well as with either the SDR or DTR mode.

The device size, as specified by DEVSIZE[4:0] in OCTOSPI_DCR1, must reflect the total external device capacity that is the double of the size of one individual component.

If address X is even, then the byte that the OCTOSPI gives for address X is the byte at the address X/2 of device A, and the byte that the OCTOSPI gives for address X + 1 is the byte at the address X/2 of device B. In other words, the bytes at even addresses are all stored in device A and the bytes at odd addresses are all stored in device B.

When reading the status registers of the devices in dual-quad configuration, twice as many bytes must be read compared to the same read in regular-command protocol: if each device gives eight valid bits after the instruction for fetching the status register, then the OCTOSPI must be configured with a data length of 2 bytes (16 bits), and the OCTOSPI receives one byte from each device.

If each device gives a status of 16 bits, then the OCTOSPI must be configured to read 4 bytes to get all the status bits of both devices in dual-quad configuration. The least-significant byte of the result (in the data register) is the least-significant byte of device A status register. The next byte is the least-significant byte of device B status register. Then, the third byte of the data register is the device A second byte. The fourth byte is the device B second byte (if devices have 16-bit status registers).

An even number of bytes must always be accessed in dual-quad configuration. For this reason, bit 0 of DL[31:0] in OCTOSPI_DLR is stuck at 1 when DMM = 1.

In dual-quad configuration, the behavior of device A interface signals is basically the same as in normal mode. Device B interface signals have exactly the same waveforms as device A ones during the instruction, address, alternate-byte, and dummy-cycle phases. In other words, each device always receives the same instruction and the same address.

Then, during the data phase, the AIOx and the BIOx buses both transfer data in parallel, but the data that is sent to (or received from) device A is distinct than the one from device B.

23.4.6 HyperBus protocol

The OCTOSPI can communicate with the external device using the HyperBus protocol.

The HyperBus uses 11 to 12 pins depending on the operating voltage:

• • IO[7:0] as bidirectional data bus
• • DQS for read and write data strobe and latency insertion
• • NCS
• • CLK
• • NCLK for 1.8 V operations (to support this mode, the device must be powered with 1.8 V)

The HyperBus does not require any command specification nor any alternate bytes. As a consequence, a separate register set is used to define the timing of the transaction.

The HyperBus frame is composed of the following phases:

• • Command/address phase
• • Data phase

The NCS falls before the start of a transaction and rises again after each transaction finishes.

Figure 146. Example of HyperBus read operation

Note: Due to internal synchronization, up to six extra dummy clock cycles may be generated by the Octo-SPI interface after the last data is read.

The specific HyperBus features are configured through the registers in the 0x0200-0x02FC offset range.

Command/address phase

During this initial phase, the OCTOSPI sends 48 bits over IO[7:0] to specify the operations to be performed with the external device.

Table 218. Command/address phase description

The address space is configured through the memory type MTYP[2:0] in OCTOSPI_DCR1.

The total size of the device must be configured through DEVSIZE[4:0] of OCTOSPI_DCR1. In case of multi-chip product (MCP), the device size is the sum of all the sizes of all the MCP dies.

Read/write operation with initial latency

The HyperBus read and write operations need to respect two timings:

• • \( t_{RWR} \) : minimal read/write recovery time for the device (defined by TRWR[7:0] in OCTOSPI_HLCR)
• • \( t_{ACC} \) : access time for the device (defined by TACC[7:0] in OCTOSPI_HLCR) according to the memory latency

During the read operation, the DQS is used by the device, in two ways (see Figure 146 ):

• • during the command/address phase, to request an additional latency
• • during the data phase, for data strobing

During the write operation, the DQS is used:

• • by the device, during the command/address phase, to request an additional latency.
• • by the OCTOSPI, during the data phase, for write data masking.

Read/write operation with additional latency

If the device needs an additional latency (during refresh period of an SDRAM for example), DQS must be tied to one during one of the DQS signals, during the command/address phase.

An additional \( t_{ACC} \) duration is added by the OCTOSPI to meet the device request.

Figure 149. HyperBus write operation with additional latency

Fixed-latency mode

Some devices or some applications may not want to operate with a variable latency time as described above.

The latency can be forced to \( 2 \times t_{ACC} \) by setting LM in OCTOSPI_HLCR.

In this OCTOSPI latency mode, the state of the DQS signal is not taken into account by the OCTOSPI, and an additional latency is always added, leading to a fixed \( 2 \times t_{ACC} \) latency time.

Write operation with no latency

Some devices can also require a zero latency for the write operations. This write-zero latency can be forced by setting WZL in OCTOSPI_HLCR.

Figure 150. HyperBus write operation with no latency (register write)

Latency on page-crossing during the read operations

An additional latency can be needed by some devices for the read operation when crossing pages.

The initial latency must be respected for any page access, as a consequence, when the first access is close to the page boundary, a latency is automatically added at the page crossing to respect the \( t_{ACC} \) time.

Figure 151. HyperBus read operation page crossing with latency

23.4.7 Specific features

The OCTOSPI supports some specific features, such as:

• • Wrap support
• • NCS boundary and refresh

Wrap support

The OCTOSPI supports a hybrid wrap as defined by the HyperBus protocol. A hybrid wrap is also supported in the regular-command protocol.

In hybrid wrap, the transaction can continue after the initial wrap with an incremental access.

The wrap size supported by the target memory is configured by WRAPSIZE in OCTOSPI_DCR2.

Wrap is supported only in memory-read direction and only for data size = 4 bytes. Wrapped reads are supported for both HyperBus and regular-command protocols. To enable wrapped-read accesses, the dedicated OCTOSPI_WPxxx registers must be programmed according to the wrapped-read access characteristics. These registers apply for both HyperBus and regular-command protocols.

If the target memory is not supporting the hybrid wrap, WRAPSIZE must be set to 0.

Note: Hybrid wrap requires that the nonwrapped registers (OCTOSPI_CCR, OCTOSPI_TCR, OCTOSPI_IR) are set according to the memory configuration to satisfy its correct data prefetch (initiated after the wrap command).

The wrap operation cannot be interrupted by a refresh. The refresh event is only considered after the wrap completion.

NCS boundary and refresh

Two processes can be activated to regulate the OCTOSPI transactions:

• • NCS boundary
• • Refresh

The NCS boundary feature limits a transaction to a boundary of aligned addresses. The size of the address to be aligned with, is configured by CSBOUND[4:0] in OCTOSPI_DCR3: it is equal to \( 2^{\text{CSBOUND}} \) .

As an example, if CSBOUND[4:0] = 0x4, the boundary is set to \( 2^4 = 16 \) bytes. The NCS is then released each time the LSB address is equal to 0xF, and each time a new transaction is issued to address the next data.

If CSBOUND[4:0] = 0, the feature is disabled. A minimum value of three is recommended.

The NCS boundary feature cannot be used for flash memory devices in write mode since a command is necessary to program another page of the flash memory.

The refresh feature limits the duration of the transactions to the value programmed by REFRESH[31:0] in OCTOSPI_DCR4. The duration is expressed in number of cycles. This allows an external RAM to perform its internal refresh operation regularly.

The refresh value must be greater than the minimal transaction size in terms of number of cycles including the command/address/alternate/dummy phases.

If NCS boundary and refresh are enabled at the same time, the NCS is released on the first condition met.

Restarting after an interrupted transfer

When a read or write operation is interrupted by a timeout or communication regulation feature, the Octo-SPI interface, as soon as possible after getting back the port ownership, reissues the initial command sequence together with the address following the last address actually accessed before interruption. The transfer initially set goes on and ends seamlessly.

23.4.8 OCTOSPI operating mode introduction

The OCTOSPI has the following operating modes regardless of the low-level protocol used (either regular-command or HyperBus):

• • indirect mode (read or write)
• • automatic status-polling mode (only in regular-command protocol)
• • memory-mapped mode

23.4.9 OCTOSPI indirect mode

In indirect mode, the commands are started by writing to the OCTOSPI registers, and data are transferred by writing or reading the data register, in a similar way to other communication peripherals.

When FMODE[1:0] = 00 in OCTOSPI_CR, the OCTOSPI is in indirect-write mode: bytes are sent to the external device during the data phase. Data are provided by writing to OCTOSPI_DR.

When FMODE[1:0] = 01, the OCTOSPI is in indirect-read mode: bytes are received from the external device during the data phase. Data are recovered by reading OCTOSPI_DR.

In indirect mode, when the OCTOSPI is configured in DTR mode over eight lanes with DQS disabled, the given starting address and the data length must be even.

Note: The OCTOSPI_AR register must be updated even if the start address is the same as the start address of the previous indirect access.

The number of bytes to be read/written is specified in OCTOSPI_DLR:

• • If DL[31:0] = 0xFFFF FFFF, the data length is considered undefined and the OCTOSPI simply continues to transfer data until it reaches the end of the external device (as

defined by DEVSIZE). If no bytes are to be transferred, DMODE[2:0] must be set to 0 in OCTOSPI_CCR.

• • If DL[31:0] = 0xFFFF FFFF and DEVSIZE[4:0] = 0x1F (its maximum value indicating at 4-Gbyte device), the transfers continue indefinitely, stopping only after an abort request or after the OCTOSPI is disabled. After the last memory address is read (at address 0xFFFF FFFF), reading continues with address = 0x0000 0000.

When the programmed number of bytes to be transmitted or received is reached, the TCF bit is set in OCTOSPI_SR, and an interrupt is generated if TCIE = 1 in OCTOSPI_CR. In the case of an undefined number of data, TCF is set when the limit of the external SPI memory is reached, according to the device size defined in OCTOSPI_DCR1.

Triggering the start of a transfer in regular-command protocol

Depending on the OCTOSPI configuration, there are three different ways to trigger the start of a transfer in indirect mode when using the regular-command protocol. In general, the start of transfer is triggered as soon as the software gives the last information that is necessary for the command. More specifically in indirect mode, a transfer starts when one of the following sequence of events occurs:

• • if no address is necessary (ADMODE[2:0] = 000) and if no data need to be provided by the software (FMODE[1:0] = 01 or DMODE[2:0] = 000), and at the moment when a write is performed to INSTRUCTION[31:0] in OCTOSPI_IR
• • if an address is necessary (when ADMODE[2:0] ≠ 000) and if no data need to be provided by the software (when FMODE[1:0] = 01 or DMODE[2:0] = 000), and at the moment when a write is performed to ADDRESS[31:0] in OCTOSPI_AR
• • if data need to be provided by the software (when FMODE[1:0] = 00 and DMODE[2:0] ≠ 000), and at the moment when a write is performed to DATA[31:0] in OCTOSPI_DR

A write to OCTOSPI_ABR never triggers the communication start. If alternate bytes are required, they must have been programmed before.

As soon as a command is started, the BUSY bit is automatically set in OCTOSPI_SR.

Triggering the start of a transfer in HyperBus protocol

Depending on the OCTOSPI configuration, there are different ways to trigger the start of a command in indirect mode. In general, it is triggered as soon as the firmware gives the last information that is necessary for the transfer to start, and more specifically, a communication in indirect mode is triggered by one of the following register settings, when it is the last one to be executed:

• • when a write is performed to ADDRESS[31:0] (OCTOSPI_AR) with ADMODE[2:0] ≠ 000 in indirect read mode (FMODE[1:0] = 01).
• • when a write is performed to DATA[31:0] (OCTOSPI_DR) in indirect-write mode (when FMODE = 00).
• • when a (dummy) write is performed to INSTRUCTION[31:0] (OCTOSPI_IR) for indirect read mode (with ADMODE[2:0] = 000 and FMODE = 01).

As soon as a transfer is started, the BUSY bit (OCTOSPI_SR[5]) is automatically set.

FIFO and data management

Data in indirect mode passes through a 32-byte FIFO that is internal to the OCTOSPI. FLEVEL in OCTOSPI_SR indicates how many bytes are currently being held in the FIFO.

AHB burst transactions are supported. Data of the burst are successively written in OCTOSPI_DR, and immediately transferred in the internal FIFO.

In indirect-write mode (FMODE[1:0] = 00), the software adds data to the FIFO when it writes in OCTOSPI_DR. A word write adds 4 bytes to the FIFO, a half-word write adds 2 bytes, and a byte write adds only 1 byte. If the software adds too many bytes to the FIFO (more than indicated in DL[31:0]), the extra bytes are flushed from the FIFO at the end of the write operation (when TCF is set).

The byte/half-word accesses to OCTOSPI_DR must be done only to the least significant byte/halfword of the 32-bit register.

FTHRES is used to define a FIFO threshold after which point the FIFO threshold flag, FTF, gets set. In indirect-read mode, FTF is set when the number of valid bytes to be read from the FIFO is above the threshold. FTF is also set if there is any data left in the FIFO after the last byte is read from the external device, regardless of FTHRES setting. In indirect-write mode, the FTF is set when the number of empty bytes in the FIFO is above the threshold.

If FTIE = 1, there is an interrupt when the FTF is set. If DMAEN = 1, a DMA transfer is initiated when the FTF is set. The FTF is cleared by hardware as soon as the threshold condition is no longer true (after enough data has been transferred by the CPU or DMA).

The last data read in RX FIFO remains valid as long as there is no request for the next line. This means that, when the application reads several times in a row at the same location, the data is provided from the RX FIFO and not read again from the distant memory.

23.4.10 OCTOSPI automatic status-polling mode

In automatic status-polling mode, the OCTOSPI periodically starts a command to read a defined number of status bytes (up to four). The received bytes can be masked to isolate some status bits and an interrupt can be generated when the selected bits have a defined value. The automatic status-polling mode must be used only in regular-command protocol. For HyperBus protocol, it is not exploitable since the read status register into the HyperFlash memory must be performed in two steps (a write operation followed by a read operation).

The access to the device begins in the same manner as in indirect-read mode. BUSY in OCTOSPI_SR goes high at this point and stays high even between the periodic accesses.

The content of MASK[31:0] in OCTOSPI_PSMAR is used to mask the data from the external device in automatic status-polling mode:

• • If the MASK[n] = 0, then bit n of the result is masked and not considered.
• • If MASK[n] = 1, and the content of bit[n] is the same as MATCH[n] in OCTOSPI_PSMAR, then there is a match for bit n.

If PMM = 0 in OCTOSPI_CR, the AND-match mode is activated: SMF is set in OCTOSPI_SR only when there is a match on all of the unmasked bits.

If PMM = 1 in OCTOSPI_CR, the OR-match mode is activated: SMF gets set if there is a match on any of the unmasked bits.

An interrupt is called when SMF = 1 if SMIE = 1.

If APMS is set in OCTOSPI_CR, the operation stops and BUSY goes to 0 as soon as a match is detected. Otherwise, BUSY stays at 1 and the periodic accesses continue until there is an abort or until the OCTOSPI is disabled (EN = 0).

OCTOSPI_DR contains the latest received status bytes (FIFO deactivated). The content of this register is not affected by the masking used in the matching logic. FTF in OCTOSPI_SR is set as soon as a new reading of the status is complete. FTF is cleared as soon as the data is read.

In automatic status-polling mode, variable latency is not supported. The memory must then be configured in fixed latency.

23.4.11 OCTOSPI memory-mapped mode

When configured in memory-mapped mode, the external SPI device is seen as an internal memory.

Note: No more than 256 Mbytes can be addressed even if the external device capacity is larger.

If an access is made to an address outside of the range defined by DEVSIZE[4:0] but still within the 256 Mbytes range, then an AHB error is given. The effect of this error depends on the AHB master that attempted the access:

• • If it is the Cortex CPU, a hard-fault interrupt is generated.
• • If it is a DMA, a DMA transfer error is generated, and the corresponding DMA channel is automatically disabled.

Byte, half-word, and word access types are all supported.

A support for execute in place (XIP) operation is implemented, where the OCTOSPI continues to load the bytes to the addresses following the most recent access. If subsequent accesses are continuous to the bytes that follow, then these operations end up quickly since their results were prefetched.

By default, the OCTOSPI never stops its prefetch operation. It either keeps the previous read operation active with the NCS maintained low or it relaunches a new transfer, even if no access to the external device occurs for a long time.

Since external devices tend to consume more power when the NCS is held low, the application may want to activate the timeout counter (TCEN = 1 in OCTOSPI_CR): the NCS is released after a period defined by TIMEOUT[15:0] in OCTOSPI_LPTR, when x cycles have elapsed without access since the clock is inactive.

BUSY goes high as soon as the first memory-mapped access occurs. Because of the prefetch operations, BUSY does not fall until there is an abort, or the peripheral is disabled.

It is not recommended to program the flash memory using the memory-mapped writes. The indirect-write mode fulfills this operation.

However, if the application requires the use of the MCE for encryption (check MCE product availability), the memory-mapped write mode may be used to program encrypted data to external flash memory under the following conditions:

• • Prefetch must be enabled.
• • In block cipher mode, the CPU must write a complete 128-bit data block to prevent the MCE from initiating read-modify-write operations when only a few bytes need to be

programmed. This precaution avoids incorrect programming operations. There are no specific constraints to respect if the MCE is used in stream cipher mode.

• • Apply the abort sequence to exit memory-mapped mode when the data linked to the page has been written in the external memory buffers. The abort sequence triggers the start of the page programming.
• • Switch to the automatic status-polling mode to monitor the completion of the page programming phase.
• • Relaunch the write enable command in indirect mode, then switch back to the memory-mapped mode configuration to continue to program additional pages if any.

It is recommended to add a synchronization barrier between the end of the controller registers configuration and the first memory-mapped access to the external memory when the controller is configured in memory-mapped mode.

23.4.12 OCTOSPI configuration introduction

The OCTOSPI configuration is done in three steps:

1. 1. OCTOSPI system configuration
2. 2. OCTOSPI device configuration
3. 3. OCTOSPI mode configuration

23.4.13 OCTOSPI system configuration

The OCTOSPI is configured using OCTOSPI_CR. The user must program:

• • the functional mode with FMODE[1:0]
• • the automatic status-polling mode behavior if needed with PMM and APMS
• • the FIFO level with FTHRES
• • the DMA use with DMAEN
• • the timeout counter use with TCEN
• • the dual-memory configuration, if needed, with DMM

In case of an interrupt use, the respective enable bit can also be set during this phase.

If the timeout counter is used, the timeout value is programmed in OCTOSPI_LPTR.

The DMA channel must not be enabled during the OCTOSPI configuration: it must be enabled only when the operation is fully configured, to avoid any unexpected request generation.

The DMA and OCTOSPI must be configured in a coherent manner regarding data length: FTHRES value must reflect the DMA burst size.

23.4.14 OCTOSPI device configuration

The parameters related to the external device targeted are configured through OCTOSPI_DCR1 and OCTOSPI_DCR2. The user must program:

• • the device size with DEVSIZE[4:0]
• • the chip-select minimum high time with CSHT[5:0]
• • the clock mode with FRCK and CKMODE
• • the device frequency with PRESCALER[7:0]

DEVSIZE[4:0] defines the size of external memory using the following formula:

where DEVSIZE+1 is the number of address bits required to address the external device. The external device capacity can go up to 4 Gbytes (addressed using 32 bits) in indirect mode, but the addressable space in memory-mapped mode is limited to 256 Mbytes.

If DMM = 1, DEVSIZE[4:0] must reflect the total capacity of the two devices together considering the above formula (DEVSIZE[4:0] value is so equal to one of the two memory capacities).

When the OCTOSPI executes two commands, one immediately after the other, it raises the chip-select signal (NCS) high between the two commands for only one CLK cycle by default.

If the external device requires more time between commands, the chip-select high time CSHT[5:0] can be used to specify the minimum number of CLK cycles for which the NCS must remain high.

CKMODE indicates the level that the CLK takes between commands (when NCS = 1).

In HyperBus protocol, the device timing ( \( t_{ACC} \) and \( t_{RWR} \) ) and the latency mode must be configured in OCTOSPI_HLCR.

Memory types

External memory providers may present some architecture and slight data formatting differences between them. The bitfield MTYP[2:0] into the OCTOSPI_CR register allows targeting the right controller configuration depending on the associated memory type selected in the application. This is the responsibility of the software developer to align the controller configuration to fit with the targeted memory type.

The memory types are grouped in a such way:

• • D0/D1 data ordering in octal-SPI data mode (DMODE[2:0] = 100) in DTR mode by configuring MTYP[2:0] = 000. For instance, Micron is using such data ordering. In this configuration, the DQS is sent with a polarity inverted respect to the clock polarity.

Figure 152. D0/D1 data ordering in octal-SPI DTR mode (Micron) - Read access

• • D1/D0 data ordering in octal-SPI data mode (DMODE[2:0] = 100) in DTR mode by configuring MTYP[2:0] = 001. For instance, Macronix is using this reverse data ordering in its Octaflash portfolio (this configuration is not adapted to its OctaRAM™ memories). DQS is keeping the same polarity as the clock when reading data from the

memory. Refer to Figure 143: DTR read in octal-SPI mode with DQS (Macronix mode) example .

• • D1/D0 data ordering in octal-SPI data mode (DMODE[2:0] = 100) in DTR mode by configuring MTYP[2:0] = 011 with specific address phase built with row and column to fit with Macronix OctaRAM™ memories requirement (refer to Table 219: OctaRAM command address bit assignment (based on 64-Mbyte OctaRAM) ). This is the controller which translates internally the targeted address provided by the software in row/column address formatting to sent to the memory. DQS is keeping the same polarity as the clock one when reading data from the memory.

Figure 153. OctaRAM read operation with reverse data ordering D1/D0

Table 219. OctaRAM command address bit assignment
(based on 64-Mbyte ⁽¹⁾ OctaRAM)

1. 1. Example of 64-Mbyte OctaRAM address assignment:
   Row Address [RA12:RA0]: 8K. Column address [CA9:CA0]: 1K. 64-Mbyte density = 8K x 1K x 8 bits
2. 2. Column address A0 must be always 0.

• • HyperBus memories need to be selected when targeted by the application. The configuration to set depends on the access type:
  • – HyperBus memory mode: The protocol follows the HyperBus specification. MTYP[2:0] = 100 is the configuration to use to access the memory space.
  • – HyperBus register mode (addressing register space): the memory-mapped accesses in this mode must be noncacheable, or the indirect read/write modes

must be used. The configuration to be set for this particular register space access is MTYP[2:0] = 101.

• • Standard mode. It is the mode to use whenever the targeted memory is not corresponding to any others configurations described in this section. MTYP[2:0] = 010 for this standard mode.

23.4.15 OCTOSPI regular-command mode configuration

Indirect mode configuration

When FMODE[1:0] = 00, the indirect-write mode is selected and data can be sent to the external device. When FMODE[1:0] = 01, the indirect-read mode is selected, and data can be read from the external device.

When the OCTOSPI is used in indirect mode, the frames are constructed in the following way:

1. 1. Specify a number of data bytes to read or write in OCTOSPI_DLR.
2. 2. Specify the frame timing in OCTOSPI_TCR.
3. 3. Specify the frame format in OCTOSPI_CCR.
4. 4. Specify the instruction in OCTOSPI_IR.
5. 5. Specify the optional alternate byte to be sent right after the address phase in OCTOSPI_ABR.
6. 6. Specify the targeted address in OCTOSPI_AR.
7. 7. Enable the DMA channel if needed.
8. 8. Read/write the data from/to the FIFO through OCTOSPI_DR (if no DMA usage).

If neither the address register (OCTOSPI_AR) nor the data register (OCTOSPI_DR) need to be updated for a particular command, then the command sequence starts as soon as OCTOSPI_IR is written. This is the case when both ADMODE[2:0] and DMODE[2:0] equal 000, or if just ADMODE[2:0] = 000 when in indirect-read mode (FMODE[1:0] = 01).

When an address is required (ADMODE[2:0] ≠ 000) and the data register does not need to be written (FMODE[1:0] = 01 or DMODE[2:0] = 000), the command sequence starts as soon as the address is updated with a write to OCTOSPI_AR.

In case of data transmission (FMODE[1:0] = 00 and DMODE[2:0] ≠ 000), the communication start is triggered by a write in the FIFO through OCTOSPI_DR.

Automatic status-polling mode configuration

The automatic status-polling mode is enabled by setting FMODE[1:0] = 10. In this mode, the programmed frame is sent and data are retrieved periodically.

The maximum amount of data read in each frame is 4 bytes. If more data is requested in OCTOSPI_DLR, it is ignored, and only 4 bytes are read. The periodicity is specified in OCTOSPI_PIR.

Once the status data has been retrieved, the following can be processed:

• • Set SMF (an interrupt is generated if enabled).
• • Stop automatically the periodic retrieving of the status bytes.

The received value can be masked with the value stored in OCTOSPI_PSMKR, and can be ORed or ANDed with the value stored in OCTOSPI_PSMAR.

In case of a match, SMF is set and an interrupt is generated if enabled. The OCTOSPI can be automatically stopped if AMPS is set. In any case, the latest retrieved value is available in OCTOSPI_DR.

When the OCTOSPI is used in automatic status-polling mode, the frames are constructed in the following way:

1. 1. Specify the input mask in OCTOSPI_PSMKR.
2. 2. Specify the comparison value in OCTOSPI_PSMAR.
3. 3. Specify the read period in OCTOSPI_PIR.
4. 4. Specify a number of data bytes to read in OCTOSPI_DLR.
5. 5. Specify the frame timing in OCTOSPI_TCR.
6. 6. Specify the frame format in OCTOSPI_CCR.
7. 7. Specify the instruction in OCTOSPI_IR.
8. 8. Specify the optional alternate byte to be sent right after the address phase in OCTOSPI_ABR.
9. 9. Specify the optional targeted address in OCTOSPI_AR.

If the address register (OCTOSPI_AR) does not need to be updated for a particular command, then the command sequence starts as soon as OCTOSPI_CCR is written. This is the case when ADMODE[2:0] = 000.

When an address is required (ADMODE[2:0] ≠ 000), the command sequence starts as soon as the address is updated with a write to OCTOSPI_AR.

Memory-mapped mode configuration

In memory-mapped mode, the external device is seen as an internal memory but with some latency during accesses. Read and write operations are allowed to the external device in this mode.

It is not recommended to program the flash memory using memory-mapped writes, as the internal flags for erase or programming status have to be polled. The indirect-write mode fulfills this operation, possibly in conjunction with the automatic status-polling mode.

The memory-mapped mode is entered by setting FMODE[1:0] = 11 in OCTOSPI_CR.

The programmed instruction and frame are sent when an AHB master accesses the memory-mapped space.

The FIFO is used as a prefetch buffer to anticipate any linear reads. Any access to OCTOSPI_DR in this mode returns zero.

The data length register (OCTOSPI_DLR) has no meaning in memory-mapped mode.

When the OCTOSPI is used in memory-mapped mode, the frames are constructed in the following way:

1. 1. Specify the frame timing in OCTOSPI_TCR for read operation.
2. 2. Specify the frame format in OCTOSPI_CCR for read operation.
3. 3. Specify the instruction in OCTOSPI_IR.
4. 4. Specify the optional alternate byte to be sent right after the address phase in OCTOSPI_ABR for read operation.
5. 5. Specify the frame timing in OCTOSPI_WTCR for write operation.
6. 6. Specify the frame format in OCTOSPI_WCCR for write operation.

1. 7. Specify the instruction in OCTOSPI_WIR.
2. 8. Specify the optional alternate byte to be sent right after the address phase in OCTOSPI_WABR for write operation.

All configuration operations must be completed (ensured by checking BUSY = 0) before the first access to the memory area: any register write operation when BUSY = 1 has no effect and is not signaled with an error response. On the first access, the OCTOSPI becomes busy, and no further configuration is allowed. Then, the only way to get BUSY low is to clear the ENABLE bit or to abort by setting the ABORT bit.

OCTOSPI delayed data sampling when no DQS is used

By default, when no DQS is used, the OCTOSPI samples the data driven by the external device one half of a CLK cycle after the external device drives the signal.

In case of any external signal delays, it may be useful to sample the data later. Using SSHIFT in OCTOSPI_TCR, the sampling of the data can be shifted by half of a CLK cycle.

The firmware must clear SSHIFT when the data phase is configured in DTR mode (DDTR = 1).

OCTOSPI delayed data sampling when DQS is used

When external DQS is used as a sampling clock, it can be shifted in time to compensate the data propagation delay. This shift is performed by an external delay block located outside the OCTOSPI. The control of this feature depends on the device implementation (see the product reference manual for more details).

In configurations where delay does not need to be compensated, the external delay block can be bypassed by setting DLYBYP in OCTOSPI_DCR1.

23.4.16 OCTOSPI HyperBus protocol configuration

Indirect mode configuration (HyperBus)

When FMODE[1:0] = 00, the indirect-write mode is selected and data can be sent to the external device. When FMODE[1:0] = 01, the indirect-read mode is selected where data can be read from the external device. ADMODE must be configured with a value different from 000 (for instance ADMODE = 100).

When the OCTOSPI is used in indirect mode, the frames are constructed in the following way:

1. 1. Specify a number of data bytes to read or write in OCTOSPI_DLR.
2. 2. Specify the targeted address in OCTOSPI_AR.
3. 3. Enable the DMA channel if needed.
4. 4. Read/write the data from/to the FIFO through OCTOSPI_DR (if no DMA usage).

In indirect-read mode, the command sequence starts as soon as the address is updated with a write to OCTOSPI_AR.

In indirect-write mode, the communication start is triggered by a write in the FIFO through OCTOSPI_DR.

Memory-mapped mode configuration (HyperBus)

In memory-mapped mode, the external device is seen as an internal memory but with some latency during the accesses. Read and write operations are allowed to the external device in this mode.

It is not recommended to program the flash memory using the memory-mapped writes: the indirect-write mode fulfills this operation.

The memory-mapped mode is entered by setting FMODE[1:0] = 11. The programmed instruction and frame is sent when an AHB master accesses the memory-mapped space.

The FIFO is used as a prefetch buffer to anticipate any linear reads. Any access to OCTOSPI_DR in this mode returns zero.

The data length register (OCTOSPI_DLR) has no meaning in memory-mapped mode.

All the configuration operation must be completed before the first access to the memory area. On the first access, the OCTOSPI becomes busy, and no configuration is allowed. Then, the only way to get BUSY low is to clear the ENABLE bit, or to abort by setting the ABORT bit.

23.4.17 OCTOSPI error management

The following errors set the TEF flag in OCTOSPI_SR and generates an interrupt if enabled (TEIE = 1 in OCTOSPI_CR):

• • in indirect or automatic status-polling mode, when a wrong address has been programmed in OCTOSPI_AR (according to the device size defined by DEVSIZE[4:0]).
• • in indirect mode, if the address plus the data length exceed the device size: TEF is set as soon as the access is triggered.

In memory-mapped mode, the OCTOSPI generates an AHB slave error in the following situations,:

• • The memory-mapped mode is disabled and an AHB read or write request occurs.
• • A read or write address exceeds the size of the external memory.
• • An abort is received while a read or write burst is ongoing.
• • The OCTOSPI is disabled while a read or write burst is requested.
• • A write wrap burst is received.
• • A write request is received while DQSE = 0 in OCTOSPI_WCCR in octal DTR mode, in dual-memory configuration, in HyperBus mode.
• • A read or write request is received while DMODE[2:0] = 000 (no data phase), except when MTYP[2:0] is HyperBus.
• • Illegal access size when wrap read burst. This means that the AHB bus transfer size (HSIZE) is different from 4 bytes (only for memory-mapped mode).
• • Bit DMM is set in OCTOSPI_CR (dual-memory configuration) and octal mode is set.

23.4.18 OCTOSPI BUSY and ABORT

Once the OCTOSPI starts an operation with the external device, BUSY is automatically set in OCTOSPI_SR.

In indirect mode, BUSY is reset once the OCTOSPI has completed the requested command sequence and the FIFO is empty.

In automatic status-polling mode, BUSY goes low only after the last periodic access is complete, due to a match when APMS = 1 or due to an abort.

After the first access in memory-mapped mode, BUSY goes low only on an abort.

Any operation can be aborted by setting ABORT in OCTOSPI_CR. Once the abort is completed, BUSY and ABORT are automatically reset, and the FIFO is flushed.

Before setting ABORT, the software must ensure that all the current transactions are finished using the synchronization barriers. When DMA is enabled to handle the data read or write operations in OCTOSPI_DR, it is recommended to disable the DMA channel before aborting the OCTOSPI.

Note: Some devices may misbehave if a write operation to a status register is aborted.

23.4.19 OCTOSPI reconfiguration or deactivation

Before any OCTOSPI reconfiguration, the software must ensure that all the transactions are completed:

• • After a memory-mapped write, the software must perform a dummy read followed by a synchronization barrier, then an abort.
• • After a memory-mapped read, the software must perform a synchronization barrier than an abort.

23.4.20 NCS behavior

By default, NCS is high, deselecting the external device. NCS falls before an operation begins and rises as soon as it finishes.

When CKMODE = 0 (clock mode 0: CLK stays low when no operation is in progress), NCS falls one CLK cycle before an operation first rising CLK edge, and NCS rises one CLK cycle after the operation final rising CLK edge (see the figure below).

Figure 154. NCS when CKMODE = 0 (T = CLK period)

When CKMODE = 1 (clock mode 3: CLK goes high when no operation is in progress) and when in SDR mode, NCS falls one CLK cycle before an operation first rising CLK edge, and NCS rises one CLK cycle after the operation final rising CLK edge (see the figure below).

Figure 155. NCS when CKMODE = 1 in SDR mode ( \( T = \text{CLK period} \) )

When the CKMODE = 1 (clock mode 3) and DDTR = 1 (data DTR mode), NCS falls one CLK cycle before an operation first rising CLK edge, and NCS rises one CLK cycle after the operation final active rising CLK edge (see the figure below). Because the DTR operations must finish with a falling edge, CLK is low when NCS rises, and CLK rises back up one half of a CLK cycle afterwards.

Figure 156. NCS when CKMODE = 1 in DTR mode ( \( T = \text{CLK period} \) )

When the FIFO stays full during a read operation, or if the FIFO stays empty during a write operation, the operation stalls and CLK stays low until the software services the FIFO. If an abort occurs when an operation is stalled, NCS rises just after the abort is requested and then CLK rises one half of a CLK cycle later (see the figure below).

Figure 157. NCS when CKMODE = 1 with an abort ( \( T = \text{CLK period} \) )

23.5 Address alignment and data number

The table below summarizes the effect of the address alignment and programmed data number depending on the use case.

Table 220. Address alignment cases

1. To be respected by the software.

2. IND = indirect mode.

3. MM = memory-mapped mode

4. Extra data at transfer start.

5. Extra data at transfer end.

6. WDM = write data mask.

1. 7. If the FTHRES bitfield is set to the maximum value with DLR value greater than the data burst length, and if the DMA is enabled or the interrupt based on FIFO THRESHOLD Flag is enabled (FTF), the address must be modulo 2 aligned in DTR mode when the initiator (DMA, CPU, ...) is writing the data with a burst length equal to the FIFO size.

23.6 OCTOSPI interrupts

An interrupt can be produced on the following events:

• • Timeout
• • Status match
• • FIFO threshold
• • Transfer complete
• • Transfer error

Separate interrupt enable bits are available to provide more flexibility.

Table 221. OCTOSPI interrupt requests

23.7 OCTOSPI registers

23.7.1 OCTOSPI control register (OCTOSPI_CR)

Address offset: 0x0000

Reset value: 0x0000 0000

Bits 31:30 Reserved, must be kept at reset value.

Bits 29:28 FMODE[1:0] : Functional mode

This bitfield defines the OCTOSPI functional mode of operation.

00: Indirect-write mode

01: Indirect-read mode

10: Automatic status-polling mode (relevant in regular-command protocol only)

11: Memory-mapped mode

If DMAEN = 1 already, then the DMA controller for the corresponding channel must be disabled before changing the FMODE[1:0] value.

Note: This bitfield can be modified only when BUSY = 0.

Bits 27:24 Reserved, must be kept at reset value.

Bit 23 PMM : Polling match mode

This bit indicates which method must be used to determine a match during the automatic status-polling mode.

0: AND-match mode, SMF is set if all the unmasked bits received from the device match the corresponding bits in the match register.

1: OR-match mode, SMF is set if any of the unmasked bits received from the device matches its corresponding bit in the match register.

Note: This bit can be modified only when BUSY = 0.

Bit 22 APMS : Automatic status-polling mode stop

This bit determines if the automatic status-polling mode is stopped after a match.

0: Automatic status-polling mode is stopped only by abort or by disabling the OCTOSPI.

1: Automatic status-polling mode stops as soon as there is a match.

Note: This bit can be modified only when BUSY = 0.

Bit 21 Reserved, must be kept at reset value.

Bit 20 TOIE : Timeout interrupt enable

This bit enables the timeout interrupt.

0: Interrupt disabled

1: Interrupt enabled

Bit 19 SMIE : Status-match interrupt enable

This bit enables the status-match interrupt.

0: Interrupt disabled

1: Interrupt enabled

Bit 18 FTIE : FIFO threshold interrupt enable

This bit enables the FIFO threshold interrupt.

0: Interrupt disabled

1: Interrupt enabled

Bit 17 TCIE : Transfer complete interrupt enable

This bit enables the transfer complete interrupt.

0: Interrupt disabled

1: Interrupt enabled

Bit 16 TEIE : Transfer error interrupt enable

This bit enables the transfer error interrupt.

0: Interrupt disabled

1: Interrupt enabled

Bits 15:13 Reserved, must be kept at reset value.

This bitfield defines, in indirect mode, the threshold number of bytes in the FIFO that causes the FIFO threshold flag FTF in OCTOSPI_SR, to be set.

00000: FTF is set if there are one or more free bytes available to be written to in the FIFO in indirect-write mode, or if there are one or more valid bytes can be read from the FIFO in indirect-read mode.

00001: FTF is set if there are two or more free bytes available to be written to in the FIFO in indirect-write mode, or if there are two or more valid bytes can be read from the FIFO in indirect-read mode.

...

11111: FTF is set if there are 32 free bytes available to be written to in the FIFO in indirect-write mode, or if there are 32 valid bytes can be read from the FIFO in indirect-read mode.

Note: If DMAEN = 1, the DMA controller for the corresponding channel must be disabled before changing the FTHRES[4:0] value.

This bit selects the external memory to be addressed in single-, dual-, quad-SPI mode in single-memory configuration (when DMM = 0).

0: External memory 1 selected (data exchanged over IO[3:0])

1: External memory 2 selected (data exchanged over IO[7:4])

This bit is ignored when DMM = 1 or when octal-SPI mode is selected.

This bit activates the dual-memory configuration, where two external devices are used simultaneously to double the throughput and the capacity

0: Dual-memory configuration disabled

1: Dual-memory configuration enabled

Note: This bit can be modified only when BUSY = 0.

This bit is valid only when the memory-mapped mode (FMODE[1:0] = 11) is selected. This bit enables the timeout counter.

0: The timeout counter is disabled, and thus the chip-select (NCS) remains active indefinitely after an access in memory-mapped mode.

1: The timeout counter is enabled, and thus the chip-select is released in the memory-mapped mode after TIMEOUT[15:0] cycles of external device inactivity.

Note: This bit can be modified only when BUSY = 0.

In indirect mode, the DMA can be used to input or output data via OCTOSPI_DR. DMA transfers are initiated when FTF is set.

0: DMA disabled for indirect mode

1: DMA enabled for indirect mode

Note: Resetting the DMAEN bit while a DMA transfer is ongoing, breaks the handshake with the DMA. Do not write this bit during DMA operation.

This bit aborts the ongoing command sequence. It is automatically reset once the abort is completed. This bit stops the current transfer.

0: No abort requested

1: Abort requested

Note: This bit is always read as 0.

Bit 0 EN : Enable

This bit enables the OCTOSPI.

0: OCTOSPI disabled

1: OCTOSPI enabled

Note: The DMA request can be aborted without having received the ACK in case this EN bit is cleared during the operation.

In case this bit is set to 0 during a DMA transfer, the REQ signal to DMA returns to inactive state without waiting for the ACK signal from DMA to be active.

23.7.2 OCTOSPI device configuration register 1 (OCTOSPI_DCR1)

Address offset: 0x0008

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:27 Reserved, must be kept at reset value.

Bits 26:24 MTYP[2:0] : Memory type

This bitfield indicates the type of memory to be supported.

000: Micron mode, D0/D1 ordering in DTR 8-data-bit mode. regular-command protocol in single-, dual-, quad- and octal-SPI modes.

Note: In this mode, DQS signal polarity is inverted with respect to the memory clock signal. This is the default value and care must be taken to change MTYP[2:0] for memories different from Micron.

001: Macronix mode, D1/D0 ordering in DTR 8-data-bit mode. Regular-command protocol in single-, dual-, quad-, and octal-SPI modes.

010: Standard mode

011: Macronix RAM mode, D1/D0 ordering in DTR 8-data-bit mode. Regular-command protocol in single-, dual-, quad-, and octal-SPI modes with dedicated address mapping (address is built with row and column to fit with Macronix requirements).

100: HyperBus memory mode, the protocol follows the HyperBus specification.

101: HyperBus register mode, addressing register space. The memory-mapped accesses in this mode must be noncacheable, or indirect-read/write modes must be used.

Others: Reserved

Bits 23:21 Reserved, must be kept at reset value.

This bitfield defines the size of the external device using the following formula:

Number of bytes in device = \( 2^{[\text{DEVSIZE}+1]} \) .

DEVSIZE + 1 is effectively the number of address bits required to address the external device. The device capacity can be up to 4 Gbytes (addressed using 32-bits) in indirect mode, but the addressable space in memory-mapped mode is limited to 256 Mbytes.

In regular-command protocol, if DMM = 1, DEVSIZE[4:0] must reflect the total capacity of the two devices together considering the above formula (DEVSIZE[4:0] value is so equal to one of the two memory capacities).

Bits 15:14 Reserved, must be kept at reset value.

CSHT + 1 defines the minimum number of CLK cycles where the chip-select (NCS) must remain high between commands issued to the external device.

0x0: NCS stays high for at least 1 cycle between external device commands.

0x1: NCS stays high for at least 2 cycles between external device commands.

...

0x3F: NCS stays high for at least 64 cycles between external device commands.

Bits 7:4 Reserved, must be kept at reset value.

0: The internal sampling clock (called feedback clock) or the DQS data strobe external signal is delayed by the delay block (for more details on this block, refer to the dedicated section of the reference manual as it is not part of the OCTOSPI peripheral).

1: The delay block is bypassed, so the internal sampling clock or the DQS data strobe external signal is not affected by the delay block. The delay is shorter than when the delay block is not bypassed, even with the delay value set to minimum value in delay block.

Bit 2 Reserved, must be kept at reset value.

This bit configures the free running clock.

0: CLK is not free running.

1: CLK is free running (always provided).

Note: Free running clock mode is intended for delay calibration only. No memory or other device access is possible when FRCK is set. Once the bit has been set to 1, the BSY bit is set, the NCS signal remains set to 1 and the clock is sent. The only way to stop the clock is to perform an abort (which clears the BSY bit). Then, the FRCK bit must be cleared by software to allow controller transactions to take place with the external memory.

This bit indicates the level taken by the CLK between commands (when NCS = 1).

0: CLK must stay low while NCS is high (chip-select released). This is referred to as clock mode 0.

1: CLK must stay high while NCS is high (chip-select released). This is referred to as clock mode 3.

23.7.3 OCTOSPI device configuration register 2 (OCTOSPI_DCR2)

Address offset: 0x000C

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:19 Reserved, must be kept at reset value.

Bits 18:16 WRAPSIZE[2:0] : Wrap size

This bitfield indicates the wrap size to which the memory is configured. For memories which have a separate command for wrapped instructions, this bitfield indicates the wrap-size associated with the command held in the OCTOSPI1_WPIR register.

000: Wrapped reads are not supported by the memory.

010: External memory supports wrap size of 16 bytes.

011: External memory supports wrap size of 32 bytes.

100: External memory supports wrap size of 64 bytes.

101: External memory supports wrap size of 128 bytes.

Others: Reserved

Bits 15:8 Reserved, must be kept at reset value.

Bits 7:0 PRESCALER[7:0] : Clock prescaler

This bitfield defines the scaler factor for generating the CLK based on the kernel clock (value + 1).

0: \( F_{CLK} = F_{KERNEL} \) , kernel clock used directly as OCTOSPI CLK (prescaler bypassed). In this case, if the DTR mode is used, it is mandatory to provide to the OCTOSPI a kernel clock that has 50% duty-cycle.

1: \( F_{CLK} = F_{KERNEL}/2 \)

2: \( F_{CLK} = F_{KERNEL}/3 \)

...

255: \( F_{CLK} = F_{KERNEL}/256 \)

For odd clock division factors, the CLK duty cycle is not 50 %. The clock signal remains low one cycle longer than it stays high.

23.7.4 OCTOSPI device configuration register 3 (OCTOSPI_DCR3)

Address offset: 0x0010

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:21 Reserved, must be kept at reset value.

Bits 20:16 CSBOUND[4:0] : NCS boundary

This bitfield enables the transaction boundary feature. When active, a minimum value of 3 is recommended. The NCS is released on each boundary of \( 2^{\text{CSBOUND}} \) bytes.

0: NCS boundary disabled

Others: NCS boundary set to \( 2^{\text{CSBOUND}} \) bytes

Bits 15:0 Reserved, must be kept at reset value.

23.7.5 OCTOSPI device configuration register 4 (OCTOSPI_DCR4)

Address offset: 0x0014

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:0 REFRESH[31:0] : Refresh rate

This bitfield enables the refresh rate feature. The NCS is released every REFRESH + 1 clock cycles for writes, and REFRESH + 4 clock cycles for reads. These two values can be extended with few clock cycles when refresh occurs during a byte transmission in single-, dual- or quad-SPI mode, because the byte transmission must be completed.

0: Refresh disabled

Others: Maximum communication length is set to REFRESH + 1 clock cycles.

Note: REFRESH count is based on the divided clock period: if OCTOSPI_DCR2 PRESCALER bitfield is changed, the REFRESH field must be updated accordingly.

23.7.6 OCTOSPI status register (OCTOSPI_SR)

Address offset: 0x0020

Reset value: 0x0000 0000

Bits 31:14 Reserved, must be kept at reset value.

Bits 13:8 FLEVEL[5:0] : FIFO level

This bitfield gives the number of valid bytes that are being held in the FIFO. FLEVEL = 0 when the FIFO is empty, and 32 when it is full.

In automatic status-polling mode, FLEVEL is zero.

Bits 7:6 Reserved, must be kept at reset value.

Bit 5 BUSY : Busy

This bit is set when an operation is ongoing. It is cleared automatically when the operation with the external device is finished and the FIFO is empty.

Bit 4 TOF : Timeout flag

This bit is set when timeout occurs. It is cleared by writing 1 to CTOF.

Bit 3 SMF : Status match flag

This bit is set in automatic status-polling mode when the unmasked received data matches the corresponding bits in the match register (OCTOSPI_PSMAR).

It is cleared by writing 1 to CSMF.

Bit 2 FTF : FIFO threshold flag

In indirect mode, this bit is set when the FIFO threshold has been reached, or if there is any data left in the FIFO after the reads from the external device are complete.

It is cleared automatically as soon as the threshold condition is no longer true.

In automatic status-polling mode, this bit is set every time the status register is read, and the bit is cleared when the data register is read.

Bit 1 TCF : Transfer complete flag

This bit is set in indirect mode when the programmed number of data has been transferred or in any mode when the transfer has been aborted. It is cleared by writing 1 to CTCF.

Bit 0 TEF : Transfer error flag

This bit is set in indirect mode when an invalid address is being accessed in indirect mode. It is cleared by writing 1 to CTEF.

23.7.7 OCTOSPI flag clear register (OCTOSPI_FCR)

Address offset: 0x0024

Reset value: 0x0000 0000

Bits 31:5 Reserved, must be kept at reset value.

Bit 4 CTOF : Clear timeout flag
Writing 1 clears the TOF flag in the OCTOSPI_SR register.

Bit 3 CSMF : Clear status match flag
Writing 1 clears the SMF flag in the OCTOSPI_SR register.

Bit 2 Reserved, must be kept at reset value.

Bit 1 CTCF : Clear transfer complete flag
Writing 1 clears the TCF flag in the OCTOSPI_SR register.

Bit 0 CTEF : Clear transfer error flag
Writing 1 clears the TEF flag in the OCTOSPI_SR register.

23.7.8 OCTOSPI data length register (OCTOSPI_DLR)

Address offset: 0x0040

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:0 DL[31:0] : Data length

Number of data to be retrieved (value+1) in indirect and automatic status-polling modes. A value not greater than three (indicating 4 bytes) must be used for automatic status-polling mode.

All 1's in indirect mode means undefined length, where OCTOSPI continues until the end of the memory, as defined by DEVSIZE.

0x0000_0000: 1 byte is to be transferred.

0x0000_0001: 2 bytes are to be transferred.

0x0000_0002: 3 bytes are to be transferred.

0x0000_0003: 4 bytes are to be transferred.

...

0xFFFF_FFFD: 4,294,967,294 (4G-2) bytes are to be transferred.

0xFFFF_FFFE: 4,294,967,295 (4G-1) bytes are to be transferred.

0xFFFF_FFFF: undefined length; all bytes, until the end of the external device, (as defined by DEVSIZE) are to be transferred. Continue reading indefinitely if DEVSIZE = 0x1F.

DL[0] is stuck at 1 in dual-memory configuration (DMM = 1) even when 0 is written to this bit, thus assuring that each access transfers an even number of bytes.

This bitfield has no effect in memory-mapped mode.

23.7.9 OCTOSPI address register (OCTOSPI_AR)

Address offset: 0x0048

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0 and FMODE ≠ 11.

Bits 31:0 ADDRESS[31:0] : Address

Address to be sent to the external device. In HyperBus protocol, this field must be even as this protocol is 16-bit word oriented. In dual-memory configuration, AR[0] is forced to 0.

23.7.10 OCTOSPI data register (OCTOSPI_DR)

Address offset: 0x0050

Reset value: 0x0000 0000

Data to be sent/received to/from the external SPI device

In indirect-write mode, data written to this register is stored on the FIFO before it is sent to the external device during the data phase. If the FIFO is too full, a write operation is stalled until the FIFO has enough space to accept the amount of data being written.

In indirect-read mode, reading this register gives (via the FIFO) the data that was received from the external device. If the FIFO does not have as many bytes as requested by the read operation and if BUSY = 1, the read operation is stalled until enough data is present or until the transfer is complete, whichever happens first.

In automatic status-polling mode, this register contains the last data read from the external device (without masking).

Word, half-word, and byte accesses to this register are supported. In indirect-write mode, a byte write adds 1 byte to the FIFO, a half-word write 2 bytes, and a word write 4 bytes.

Similarly, in indirect-read mode, a byte read removes 1 byte from the FIFO, a halfword read 2 bytes, and a word read 4 bytes. Accesses in indirect mode must be aligned to the bottom of this register: A byte read must read DATA[7:0] and a half-word read must read DATA[15:0].

23.7.11 OCTOSPI polling status mask register (OCTOSPI_PSMKR)

Address offset: 0x0080

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Mask to be applied to the status bytes received in automatic status-polling mode

For bit n:

0: Bit n of the data received in automatic status-polling mode is masked and its value is not considered in the matching logic.

1: Bit n of the data received in automatic status-polling mode is unmasked and its value is considered in the matching logic.

23.7.12 OCTOSPI polling status match register (OCTOSPI_PSMAR)

Address offset: 0x0088

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:0 MATCH[31:0] : Status match

Value to be compared with the masked status register to get a match

23.7.13 OCTOSPI polling interval register (OCTOSPI_PIR)

Address offset: 0x0090

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:16 Reserved, must be kept at reset value.

Bits 15:0 INTERVAL[15:0] : Polling interval

Number of CLK cycles between a read during the automatic status-polling phases

23.7.14 OCTOSPI communication configuration register (OCTOSPI_CCR)

Address offset: 0x0100

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:30 Reserved, must be kept at reset value.

Bit 29 DQSE : DQS enable

This bit enables the data strobe management.

0: DQS disabled

1: DQS enabled

Bit 28 Reserved, must be kept at reset value.

Bit 27 DDTR : Data double transfer rate

This bit sets the DTR mode for the data phase.

0: DTR mode disabled for data phase

1: DTR mode enabled for data phase

Bits 26:24 DMODE[2:0] : Data mode

This bitfield defines the data phase mode of operation.

000: No data

001: Data on a single line

010: Data on two lines

011: Data on four lines

100: Data on eight lines

Others: Reserved

Bits 23:22 Reserved, must be kept at reset value.

Bits 21:20 ABSIZE[1:0] : Alternate-byte size

This bitfield defines the alternate-byte size.

00: 8-bit alternate bytes

01: 16-bit alternate bytes

10: 24-bit alternate bytes

11: 32-bit alternate bytes

Bit 19 ABDTR : Alternate- byte double transfer rate

This bit sets the DTR mode for the alternate-byte phase.

0: DTR mode disabled for the alternate-byte phase

1: DTR mode enabled for the alternate-byte phase

Bits 18:16 ABMODE[2:0] : Alternate-byte mode

This bitfield defines the alternate-byte phase mode of operation.

000: No alternate bytes

001: Alternate bytes on a single line

010: Alternate bytes on two lines

011: Alternate bytes on four lines

100: Alternate bytes on eight lines

Others: Reserved

Bits 15:14 Reserved, must be kept at reset value.

Bits 13:12 ADSIZE[1:0] : Address size

This bitfield defines the address size.

00: 8-bit address

01: 16-bit address

10: 24-bit address

11: 32-bit address

Bit 11 ADDTR : Address double transfer rate

This bit sets the DTR mode for the address phase.

0: DTR mode disabled for the address phase

1: DTR mode enabled for the address phase

Bits 10:8 ADMODE[2:0] : Address mode

This bitfield defines the address phase mode of operation.

000: No address

001: Address on a single line

010: Address on two lines

011: Address on four lines

100: Address on eight lines

Others: Reserved

Bits 7:6 Reserved, must be kept at reset value.

Bits 5:4 ISIZE[1:0] : Instruction size

This bitfield defines instruction size.

00: 8-bit instruction

01: 16-bit instruction

10: 24-bit instruction

11: 32-bit instruction

Bit 3 IDTR : Instruction double transfer rate

This bit sets the DTR mode for the instruction phase.

0: DTR mode disabled for the instruction phase

1: DTR mode enabled for the instruction phase

Bits 2:0 IMODE[2:0] : Instruction mode

This bitfield defines the instruction phase mode of operation.

000: No instruction

001: Instruction on a single line

010: Instruction on two lines

011: Instruction on four lines

100: Instruction on eight lines

Others: Reserved

23.7.15 OCTOSPI timing configuration register (OCTOSPI_TCR)

Address offset: 0x0108

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bit 31 Reserved, must be kept at reset value.

Bit 30 SSHIFT : Sample shift

By default, the OCTOSPI samples data 1/2 of a CLK cycle after the data is driven by the external device.
This bit allows the data to be sampled later in order to consider the external signal delays.

0: No shift

1: 1/2 cycle shift

The software must ensure that SSHIFT = 0 when the data phase is configured in DTR mode (when DDTR = 1.)

Bit 29 Reserved, must be kept at reset value.

Bit 28 DHQC : Delay hold quarter cycle

0: No delay hold

1: 1/4 cycle hold

Bits 27:5 Reserved, must be kept at reset value.

Bits 4:0 DCYC[4:0] : Number of dummy cycles

This bitfield defines the duration of the dummy phase according to the memory latency.
In both SDR and DTR modes, it specifies a number of CLK cycles (0-31).

23.7.16 OCTOSPI instruction register (OCTOSPI_IR)

Address offset: 0x0110

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:0 INSTRUCTION[31:0] : Instruction

Instruction to be sent to the external SPI device

23.7.17 OCTOSPI alternate bytes register (OCTOSPI_ABR)

Address offset: 0x0120

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:0 ALTERNATE[31:0] : Alternate bytes
Optional data to be sent to the external SPI device right after the address.

23.7.18 OCTOSPI low-power timeout register (OCTOSPI_LPTR)

Address offset: 0x00130

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:16 Reserved, must be kept at reset value.

Bits 15:0 TIMEOUT[15:0] : Timeout period
After each access in memory-mapped mode, the OCTOSPI prefetches the subsequent bytes and hold them in the FIFO.
This bitfield indicates how many CLK cycles the OCTOSPI waits after the clock becomes inactive and until it raises the NCS, putting the external device in a lower-consumption state.

23.7.19 OCTOSPI wrap communication configuration register (OCTOSPI_WPCCR)

Address offset: 0x0140

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:30 Reserved, must be kept at reset value.

Bit 29 DQSE : DQS enable
This bit enables the data strobe management.
0: DQS disabled
1: DQS enabled

Bit 28 Reserved, must be kept at reset value.

Bit 27 DDTR : Data double transfer rate

This bit sets the DTR mode for the data phase.

0: DTR mode disabled for the data phase

1: DTR mode enabled for the data phase

Bits 26:24 DMODE[2:0] : Data mode

This bitfield defines the data phase mode of operation.

000: No data

001: Data on a single line

010: Data on two lines

011: Data on four lines

100: Data on eight lines

Others: Reserved

Bits 23:22 Reserved, must be kept at reset value.

Bits 21:20 ABSIZE[1:0] : Alternate-byte size

This bitfield defines the alternate-byte size.

00: 8-bit alternate bytes

01: 16-bit alternate bytes

10: 24-bit alternate bytes

11: 32-bit alternate bytes

Bit 19 ABDTR : Alternate-byte double transfer rate

This bit sets the DTR mode for the alternate-byte phase.

0: DTR mode disabled for the alternate-byte phase

1: DTR mode enabled for the alternate-byte phase

Bits 18:16 ABMODE[2:0] : Alternate-byte mode

This bitfield defines the alternate-byte phase mode of operation.

000: no alternate bytes

001: alternate bytes on a single line

010: alternate bytes on two lines

011: alternate bytes on four lines

100: alternate bytes on eight lines

Others: reserved

Bits 15:14 Reserved, must be kept at reset value.

Bits 13:12 ADSIZE[1:0] : Address size

This bitfield defines the address size.

00: 8-bit address

01: 16-bit address

10: 24-bit address

11: 32-bit address

Bit 11 ADDTR : Address double transfer rate

This bit sets the DTR mode for the address phase.

0: DTR mode disabled for address phase

1: DTR mode enabled for address phase

Bits 10:8 ADMODE[2:0] : Address mode

This bitfield defines the address phase mode of operation.

• 000: No address
• 001: Address on a single line
• 010: Address on two lines
• 011: Address on four lines
• 100: Address on eight lines
• Others: Reserved

Bits 7:6 Reserved, must be kept at reset value.

Bits 5:4 ISIZE[1:0] : Instruction size

This bitfield defines the instruction size.

• 00: 8-bit instruction
• 01: 16-bit instruction
• 10: 24-bit instruction
• 11: 32-bit instruction

Bit 3 IDTR : Instruction double transfer rate

This bit sets the DTR mode for the instruction phase.

• 0: DTR mode disabled for the instruction phase
• 1: DTR mode enabled for the instruction phase

Bits 2:0 IMODE[2:0] : Instruction mode

This bitfield defines the instruction phase mode of operation.

• 000: No instruction
• 001: Instruction on a single line
• 010: Instruction on two lines
• 011: Instruction on four lines
• 100: Instruction on eight lines
• Others: Reserved

23.7.20 OCTOSPI wrap timing configuration register (OCTOSPI_WPTCR)

Address offset: 0x0148

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bit 31 Reserved, must be kept at reset value.

Bit 30 SSHIFT : Sample shift

By default, the OCTOSPI samples data 1/2 of a CLK cycle after the data is driven by the external device.

This bit allows the data to be sampled later in order to consider the external signal delays.

0: No shift

1: 1/2 cycle shift

The firmware must assure that SSHIFT=0 when the data phase is configured in DTR mode (when DDTR = 1).

Bit 29 Reserved, must be kept at reset value.

Bit 28 DHQC : Delay hold quarter cycle

Add a quarter cycle delay on the outputs in DTR communication to match hold requirement.

0: No quarter cycle delay

1: 1/4 cycle delay inserted

Bits 27:5 Reserved, must be kept at reset value.

Bits 4:0 DCYC[4:0] : Number of dummy cycles

This bitfield defines the duration of the dummy phase according to the memory latency.

In both SDR and DTR modes, it specifies a number of CLK cycles (0-31).

23.7.21 OCTOSPI wrap instruction register (OCTOSPI_WPIR)

Address offset: 0x0150

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:0 INSTRUCTION[31:0] : Instruction

Instruction to be sent to the external SPI device

23.7.22 OCTOSPI wrap alternate bytes register (OCTOSPI_WPABR)

Address offset: 0x0160

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:0 ALTERNATE[31:0] : Alternate bytes

Optional data to be sent to the external SPI device right after the address

23.7.23 OCTOSPI write communication configuration register (OCTOSPI_WCCR)

Address offset: 0x0180

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0. Its content has a meaning only when requesting write operations in memory-mapped mode.

Bits 31:30 Reserved, must be kept at reset value.

Bit 29 DQSE : DQS enable

This bit enables the data strobe management.

0: DQS disabled

1: DQS enabled

Bit 28 Reserved, must be kept at reset value.

Bit 27 DDTR : data double transfer rate

This bit sets the DTR mode for the data phase.

0: DTR mode disabled for the data phase

1: DTR mode enabled for the data phase

Bits 26:24 DMODE[2:0] : Data mode

This bitfield defines the data phase mode of operation.

000: No data

001: Data on a single line

010: Data on two lines

011: Data on four lines

100: Data on eight lines

Others: Reserved

Bits 23:22 Reserved, must be kept at reset value.

Bits 21:20 ABSIZE[1:0] : Alternate-byte size

This bitfield defines the alternate-byte size.

00: 8-bit alternate bytes

01: 16-bit alternate bytes

10: 24-bit alternate bytes

11: 32-bit alternate bytes

Bit 19 ABDTR : Alternate bytes double transfer rate

This bit sets the DTR mode for the alternate-bytes phase.

0: DTR mode disabled for alternate-bytes phase

1: DTR mode enabled for alternate-bytes phase

Bits 18:16 ABMODE[2:0] : Alternate-byte mode

This bitfield defines the alternate-byte phase mode of operation.

000: No alternate bytes

001: Alternate bytes on a single line

010: Alternate bytes on two lines

011: Alternate bytes on four lines

100: Alternate bytes on eight lines

Others: Reserved

Bits 15:14 Reserved, must be kept at reset value.

Bits 13:12 ADSIZE[1:0] : Address size

This bitfield defines the address size.

00: 8-bit address

01: 16-bit address

10: 24-bit address

11: 32-bit address

Bit 11 ADDTR : Address double transfer rate

This bit sets the DTR mode for the address phase.

0: DTR mode disabled for the address phase

1: DTR mode enabled for the address phase

Bits 10:8 ADMODE[2:0] : Address mode

This bitfield defines the address phase mode of operation.

000: No address

001: Address on a single line

010: Address on two lines

011: Address on four lines

100: Address on eight lines

Others: Reserved

Bits 7:6 Reserved, must be kept at reset value.

Bits 5:4 ISIZE[1:0] : Instruction size

This bitfield defines the instruction size.

00: 8-bit instruction

01: 16-bit instruction

10: 24-bit instruction

11: 32-bit instruction

Bit 3 IDTR : Instruction double transfer rate

This bit sets the DTR mode for the instruction phase.

0: DTR mode disabled for instruction phase

1: DTR mode enabled for instruction phase

Bits 2:0 IMODE[2:0] : Instruction mode

This bitfield defines the instruction phase mode of operation.

000: No instruction

001: Instruction on a single line

010: Instruction on two lines

011: Instruction on four lines

100: Instruction on eight lines

Others: Reserved

23.7.24 OCTOSPI write timing configuration register (OCTOSPI_WTCR)

Address offset: 0x0188

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0. Its content has a meaning only when requesting write operations in memory-mapped mode.

Bits 31:5 Reserved, must be kept at reset value.

Bits 4:0 DCYC[4:0] : Number of dummy cycles

This bitfield defines the duration of the dummy phase according to the memory latency.

In both SDR and DTR modes, it specifies a number of CLK cycles (0-31).

23.7.25 OCTOSPI write instruction register (OCTOSPI_WIR)

Address offset: 0x0190

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0. Its content has a meaning only when requesting write operations in memory-mapped mode.

Bits 31:0 INSTRUCTION[31:0] : Instruction

Instruction to be sent to the external SPI device

23.7.26 OCTOSPI write alternate bytes register (OCTOSPI_WABR)

Address offset: 0x01A0

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0. Its content has a meaning only when requesting write operations in memory-mapped mode.

Bits 31:0 ALTERNATE[31:0] : Alternate bytes
Optional data to be sent to the external SPI device right after the address

23.7.27 OCTOSPI HyperBus latency configuration register (OCTOSPI_HLCR)

Address offset: 0x0200

Reset value: 0x0000 0000

This register can be modified only when BUSY = 0.

Bits 31:24 Reserved, must be kept at reset value.

Bits 23:16 TRWR[7:0] : Read-write minimum recovery time
Device read-to-write/write-to-read minimum recovery time expressed in number of communication clock cycles

Bits 15:8 TACC[7:0] : Access time
Device access time according to the memory latency, expressed in number of communication clock cycles

Bits 7:2 Reserved, must be kept at reset value.

Bit 1 WZL : Write zero latency
This bit enables zero latency on write operations.
0: Latency on write accesses
1: No latency on write accesses

Bit 0 LM : Latency mode
This bit selects the latency mode.
0: Variable initial latency
1: Fixed latency

23.7.28 OCTOSPI register map

Table 222. OCTOSPI register map and reset values

Table 222. OCTOSPI register map and reset values (continued)

Table 222. OCTOSPI register map and reset values (continued)