1. Documentation conventions
1.1 General information
The STM32H745/755 and STM32H747/757 devices embed an Arm ®(a) Cortex ® -M4 with FPU and an Arm ® Cortex ® -M7 with FPU core.
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1.2 List of abbreviations for registers
The following abbreviations (b) are used in register descriptions:
| read/write (rw) | Software can read and write to this bit. |
| read-only (r) | Software can only read this bit. |
| write-only (w) | Software can only write to this bit. Reading this bit returns the reset value. |
| read/clear write0 (rc_w0) | Software can read as well as clear this bit by writing 0. Writing 1 has no effect on the bit value. |
| read/clear write1 (rc_w1) | Software can read as well as clear this bit by writing 1. Writing 0 has no effect on the bit value. |
| read/clear write (rc_w) | Software can read as well as clear this bit by writing to the register. The value written to this bit is not important. |
| read/clear by read (rc_r) | Software can read this bit. Reading this bit automatically clears it to 0. Writing this bit has no effect on the bit value. |
| read/set by read (rs_r) | Software can read this bit. Reading this bit automatically sets it to 1. Writing this bit has no effect on the bit value. |
| read/set (rs) | Software can read as well as set this bit. Writing 0 has no effect on the bit value. |
| read/write once (rwo) | Software can only write once to this bit and can also read it at any time. Only a reset can return the bit to its reset value. |
| toggle (t) | The software can toggle this bit by writing 1. Writing 0 has no effect. |
| read-only write trigger (rt_w1) | Software can read this bit. Writing 1 triggers an event but has no effect on the bit value. |
| Reserved (Res.) | Reserved bit, must be kept at reset value. |
a. Arm is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere.
b. This is an exhaustive list of all abbreviations applicable to STMicroelectronics microcontrollers, some of them may not be used in the current document.
1.3 Glossary
This section gives a brief definition of acronyms and abbreviations used in this document:
- • Word : data of 32-bit length.
- • Half-word : data of 16-bit length.
- • Byte : data of 8-bit length.
- • Double word : data of 64-bit length.
- • Flash word : data of 256-bit length
- • IAP (in-application programming) : IAP is the ability to re-program the flash memory of a microcontroller while the user program is running.
- • ICP (in-circuit programming) : ICP is the ability to program the flash memory of a microcontroller using the JTAG protocol, the SWD protocol or the bootloader while the device is mounted on the user application board.
- • Option bytes : product configuration bits stored in the flash memory.
- • AHB : advanced high-performance bus.
- • APB : advanced peripheral bus.
- • AXI : Advanced extensible interface protocol.
- • PCROP : proprietary code readout protection.
- • RDP : readout protection.
1.4 Availability of peripherals
For availability of peripherals and their number across all sales types, refer to the particular device datasheet.
Table 1. Availability of security features
| Security feature | STM32H755xl and STM32H757xl | STM32H745xl/G and STM32H747xl/G |
|---|---|---|
| Embedded flash memory (FLASH): – Flash Secure-only area | ||
| Security memory management: – Secure access mode – Root secure services (RSS) | Available | Not available |
| Cryptographic processor (CRYP) | ||
| Hash processor (HASH) |