1. Documentation conventions
The STM32F411xx devices have an Arm ®(a) Cortex ® -M4 with FPU core.
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1.1 List of abbreviations for registers
The following abbreviations are used in register descriptions:
| read/write (rw) | Software can read and write to these bits. |
| read-only (r) | Software can only read these bits. |
| write-only (w) | Software can only write to this bit. Reading the bit returns the reset value. |
| read/clear (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 (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 by read (rc_r) | Software can read this bit. Reading this bit automatically clears it to '0'. Writing '0' 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-only write trigger (rt_w) | Software can read this bit. Writing '0' or '1' triggers an event but has no effect on the bit value. |
| toggle (t) | Software can only toggle this bit by writing '1'. Writing '0' has no effect. |
| 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.
1.2 Glossary
This section gives a brief definition of acronyms and abbreviations used in this document:
- • The CPU core integrates two debug ports:
- – JTAG debug port (JTAG-DP) provides a 5-pin standard interface based on the Joint Test Action Group (JTAG) protocol.
- – SWD debug port (SWD-DP) provides a 2-pin (clock and data) interface based on the Serial Wire Debug (SWD) protocol.
For both the JTAG and SWD protocols, please refer to the Cortex ® -M4 with FPU Technical Reference Manual
- • Word: data/instruction of 32-bit length.
- • Half word: data/instruction of 16-bit length.
- • Byte: data of 8-bit length.
- • Double word: data of 64-bit length.
- • IAP (in-application programming): IAP is the ability to reprogram 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.
- • I-Code: this bus connects the Instruction bus of the CPU core to the Flash instruction interface. Prefetch is performed on this bus.
- • D-Code: this bus connects the D-Code bus (literal load and debug access) of the CPU to the Flash data interface.
- • Option bytes: product configuration bits stored in the flash memory.
- • OBL: option byte loader.
- • AHB: advanced high-performance bus.
- • CPU: refers to the Cortex ® -M4 with FPU core.
1.3 Peripheral availability
For information on the availability and the number of instances of each peripheral, refer to the STM32F411xC/E datasheet.