Author: System on Chips

Understanding CMSIS-Driver API Groups and Their Scope The Cortex Microcontroller Software Interface Standard (CMSIS) is a vendor-independent hardware abstraction layer for microcontrollers based on ARM Cortex processors. The CMSIS-Driver specification defines a set of generic peripheral driver interfaces that enable consistent software development across different microcontroller vendors. The CMSIS-Driver API groups are categorized into communication…

ARM Cortex-A MMU Permission Fault Level 2 During MMU Initialization The issue at hand involves a Permission Fault at Level 2 when enabling the Memory Management Unit (MMU) on an ARM Cortex-A processor. The fault is indicated by the Exception Syndrome Register (ESR_EL1) with a value of 0x8600000E, which decodes to a Permission Fault at…

ARM Cortex-M7 and Cortex-M4 Cycle Count Parity in arm_dot_q15 The ARM Cortex-M7 and Cortex-M4 are both widely used microcontroller cores, but they are designed for different performance tiers. The Cortex-M7 is a higher-performance core with features like a dual-issue superscalar pipeline, branch prediction, and optional cache, while the Cortex-M4 is optimized for lower power consumption…

ARM Cortex-A15 Data Abort Exception During SDRAM Size Detection The core issue revolves around the ARM Cortex-A15 processor encountering a data abort exception when attempting to detect the size of SDRAM in a uBoot bootloader environment. The system is designed to support either 2GB or 4GB of SDRAM, and the detection mechanism involves writing to…

Flash Memory Access Latency on ARM Cortex-M4 The ARM Cortex-M4 processor, like many embedded microcontrollers, relies heavily on flash memory for storing program code and constants. However, accessing flash memory is inherently slower than accessing SRAM due to the physical characteristics of flash technology. The Cortex-M4 core itself does not dictate the exact number of…

ARM Cortex-M4 Shared Library Compilation and PLT Usage Errors The core issue revolves around the incorrect compilation and linking of shared libraries for the ARM Cortex-M4 architecture using the GCC toolchain, specifically focusing on the Procedure Linkage Table (PLT) and Global Offset Table (GOT) mechanisms. The user attempted to compile a shared library (libfun.so) and…

ARM Cortex-M7 Lockstep Configuration and Functional Safety Requirements The ARM Cortex-M7 processor is a high-performance embedded processor designed for real-time applications, particularly in automotive and industrial sectors where functional safety is paramount. One of the key features that enable functional safety in these environments is the dual-core lockstep configuration. The lockstep mechanism involves running two…

Cortex-M0 Interrupt Handler Fails to Return to Reset Handler The issue at hand involves a Cortex-M0 processor that enters an interrupt handler for a timer but fails to return to the reset handler after completing the interrupt service routine (ISR). The processor executes the timer handler correctly for the first interrupt but then gets stuck,…

STM32F407VG UART Transmission Issue with Arduino Uno as Receiver The core issue revolves around the STM32F407VG microcontroller failing to transmit the character ‘A’ via UART to an Arduino Uno, which is configured as the receiver. The STM32F407VG is programmed to send the character ‘A’ continuously in an infinite loop, but the Arduino Uno does not…

LPC546xx SWD Lockout Due to Enhanced Code Read Protection (eCRP) The LPC546xx microcontroller family, based on the ARM Cortex-M4 core, features Enhanced Code Read Protection (eCRP) as a security mechanism to prevent unauthorized access to the device’s flash memory. When eCRP is enabled, the Serial Wire Debug (SWD) interface is typically locked, rendering standard debugging…