Architectures and Processors

Cortex-M7 Usage Fault Due to Unaligned Memory Access in Idle Thread The Cortex-M7 processor, known for its high performance and advanced features, can occasionally encounter a Usage Fault triggered by an unaligned memory access. This fault is particularly challenging to diagnose when it occurs infrequently, such as every ~500 hours of runtime, and manifests as…

ARM Special Register Access Monitoring Limitations The ability to monitor access to special registers in ARM architectures, particularly in the context of debugging and performance analysis, presents a unique set of challenges. Special registers, such as SCR_EL3 in the ARMv8-A architecture, are crucial for controlling system behavior, security states, and exception handling. However, unlike general-purpose…

ARM Cortex-M7 Usage Fault Due to Illegal Unaligned Memory Access The ARM Cortex-M7 processor is a high-performance embedded processor designed for real-time applications. One of the challenges developers face when working with this processor is diagnosing and resolving usage faults, particularly those related to illegal unaligned memory accesses. An unaligned memory access occurs when a…

ARM7 CAN Code Compatibility Issues with ARM Cortex-A9 FlexCAN When attempting to port a CAN (Controller Area Network) program written for an ARM7 processor to an ARM Cortex-A9 processor, such as the one found in the i.MX6 board, several architectural and peripheral differences must be considered. The ARM7 and ARM Cortex-A9 are fundamentally different in…

Cortex-R5 Cache Initialization and Runtime Management The Cortex-R5 processor, part of ARM’s real-time processor family, is designed for high-performance and deterministic real-time applications. One of its key features is the inclusion of separate Instruction and Data Caches (I-Cache and D-Cache), which significantly improve performance by reducing memory access latency. However, configuring and managing these caches,…

ARMv8 PMU Architecture and Multicore Access Limitations The ARMv8 architecture incorporates Performance Monitoring Units (PMUs) as part of its profiling and debugging infrastructure. Each CPU core in a multicore ARMv8 system is equipped with its own dedicated PMU, which is responsible for counting and recording hardware events such as cache misses, branch mispredictions, and instruction…

ARM Cortex-M GPIO Initialization Function Argument Mismatch The core issue revolves around a function GPIO_InitPIN that has been refactored to accept a structure GPIO_PINdef instead of two separate arguments: a GPIO_TypeDef pointer and a uint16_t pin identifier. The original function signature was void GPIO_InitPIN(GPIO_TypeDef *GPIOx, uint16_t GPIO_Pin_x), which was later changed to void GPIO_InitPIN(GPIO_PINdef GPIOx)….

ARM SBCs Supporting Software Standards: TF-A, UEFI, PSCI, and SDEI When developing on ARM-based Single Board Computers (SBCs), adherence to software standards such as Trusted Firmware-A (TF-A), Unified Extensible Firmware Interface (UEFI), Power State Coordination Interface (PSCI), and Software Delegated Exception Interface (SDEI) is crucial for ensuring compatibility, security, and performance. These standards provide a…

ARM Cortex-M4 init_array_start Misalignment in Binary Output The core issue revolves around a misalignment observed in the binary output generated by the arm-none-eabi-objcopy tool when converting an ARM Executable and Linkable Format (ELF) file (.axf) to a raw binary file (.bin). Specifically, the __init_array_start__ symbol, which points to the start of the initialization function table…

NOR Flash Timing Parameter Challenges with STM32F407 Interfacing an external NOR flash memory, such as the Cypress S29GL064880TFV030, with an STM32F407 microcontroller involves precise configuration of timing parameters to ensure reliable communication. The STM32F407 microcontroller uses its Flexible Memory Controller (FMC) to interface with external memories, including NOR flash. The FMC supports multiple memory types…