Programming

Armv6-M Programming Model

The programming model used in Cortex-M processors with low power consumption. For example, Cortex-M0.

Armv7-M Programming Model

This is the programming model used in Cortex-M processors with higher performance. For example, Cortex-M4.

CMSIS

Arm specifies a standard C interface for programming Cortex-M processors, the Cortex-M Standard Interface (CMSIS). The Arm licensees are strongly encouraged to provide the CMSIS functions as part of their microcontroller programming SDK. Third-party software libraries usually rely on CMSIS availability.

Intrinsic Functions

Functions that generate instructions not provided by ISO/IEC C
Instruction	CMSIS intrinsic function
CPSIE I	void __enable_irq(void)
CPSID I	void __disable_irq(void)
ISB	void __ISB(void)
DSB	void __DSB(void)
DMB	void __DMB(void)
NOP	void __NOP(void)
REV	uint32_t __REV(uint32_t int value)
REV16	uint32_t __REV16(uint32_t int value)
REVSH	uint32_t __REVSH(uint32_t int value)
SEV	void __SEV(void)
WFE	void __WFE(void)
WFI	void __WFI(void)

Functions for accessing special registers
Register	CMSIS read function	CMSIS write function
PRIMASK	uint32_t __get_PRIMASK (void)	void __set_PRIMASK (uint32_t value)
CONTROL	uint32_t __get_CONTROL (void)	void __set_CONTROL (uint32_t value)
MSP	uint32_t __get_MSP (void)	void __set_MSP (uint32_t TopOfMainStack)
PSP	uint32_t __get_PSP (void)	void __set_PSP (uint32_t TopOfProcStack)

Processor Cores

ARM's family of Cortex-M processors (notably M0, M0+, M3, M4) are designed for use as energy-efficient microcontrollers, where M0+ is the cheapest and most efficient, and M4 is the fastest and most capable (offering DSP functions and a floating point unit).

Reference Manuals

CMSIS abstraction layer for programming Cortex-M processors

Cortex-M0+

Cortex-M4

Development Boards

Nucleo boards by STMicroelectronics, with STM32 processors
- Sold by: DigiKey, Reichelt, Conrad, etc.
Freedom boards by NXP (after buying Freescale), with Kinetis processors
LPCXpresso boards by NXP
ARM related products by Olimex

Software Development Tools

ARM Mbed framework that provides higher-level C++ API, with downloadable or web-based IDE.
GNU ARM Embedded Toolchain for Ubuntu
or the latest toolchain for all Linux distros, macOS, and Windows directly from ARM Ltd.
GNU MCU Eclipse plugin with good support for STM32
OpenOCD on-chip debugger
STM32Cube tools and drivers package for STM32 programming (CMSIS and HAL libraries)
LPCXpresso IDE and utility programs for programming LPCXpresso boards.

Arm Cortex-M