Arm

The Cortex M0 is an ultra low power 32-bit microcontroller developed by ARM Holdings. It is aimed at embedded applications that require minimal power consumption and high performance in a small physical footprint. The Cortex M0 achieves this through an efficient 3-stage pipeline, low latency interrupt handling, and extensive clock gating. In this article, we…

Interrupts are a critical part of embedded systems programming on ARM Cortex M0 chips. However, developers frequently encounter issues getting interrupts to trigger correctly. This comprehensive guide examines the common causes of interrupt problems on Cortex M0 and provides troubleshooting tips to resolve them. 1. Interrupt Handler Not Being Called The most common symptom of…

The SysTick interrupt not triggering on an ARM Cortex M0 microcontroller is often caused by improper configuration of the SysTick registers or failing to enable SysTick interrupts. The SysTick timer is a simple countdown timer built into the Cortex M0 that can generate periodic interrupts for operating system or task scheduling. This article will guide…

The reset button is an essential component on ARM Cortex microcontrollers and SoCs. Pressing the reset button restarts the processor and resets it to a known good state. This allows recovery from crashes, hangs, or other issues. The debug interface, called SWD (Serial Wire Debug), provides access to debug, programming, and profiling features built into…

JTAG and SWD are two common interfaces used for debugging and programming ARM Cortex microcontrollers. Both provide similar capabilities but have some key differences. Overview of JTAG JTAG stands for Joint Test Action Group. It is an industry standard interface originally designed for testing printed circuit boards using boundary scan. The JTAG interface has been…

The ARM Serial Wire Debug (SWD) protocol is a two-pin debug interface standard developed by ARM for debugging ARM Cortex microcontrollers. It provides a low-pin-count, high-performance alternative to JTAG for accessing and debugging ARM cores. Overview of ARM SWD ARM SWD uses just two signals for bidirectional communication – SWCLK and SWDIO. SWCLK (Serial Wire…

The Cortex-M0+ processor implements two stack pointers, known as the Main Stack Pointer (MSP) and Process Stack Pointer (PSP). These stack pointers enable low-latency context switching between different execution threads or tasks running on the Cortex-M0+ core. MSP and PSP Overview The MSP is used to store the context of exception handlers and privileges software…

When an ARM Cortex-M processor comes out of reset, it will start executing code from the vector table located at address 0x00000000. The processor expects the first entry in the vector table to be the initial stack pointer value. This initial stack pointer value determines whether the Main Stack Pointer (MSP) or Process Stack Pointer…

The Cortex-M processor is an extremely popular 32-bit ARM processor optimized for embedded applications. One of the defining characteristics of Cortex-M is that its first word must be configured as the initial stack pointer. This design choice provides some important benefits but also has tradeoffs. Understanding why the stack pointer is set up this way…

The stack pointer (SP) and link register (LR) are important registers used for function calls and returns in ARM processors. The SP points to the top of the stack, while the LR stores the return address when a function call is made. Stack Pointer (SP) The stack is a region of memory used for temporary…