Architectures and Processors

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 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-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 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…

GNU Toolchain Installation Challenges for ARM Cortex-A on macOS 10.14 The process of setting up a GNU toolchain for compiling ARM Cortex-A code on macOS 10.14 presents several challenges, particularly due to the lack of pre-built binaries for macOS and the confusion surrounding the correct architecture options. This guide will address the core issues, explore…

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…

ARM Cortex-M23 Secure and Non-Secure State Transition Issues The Nuvoton M2351 microcontroller, based on the ARM Cortex-M23 processor, is designed to support ARMv8-M security extensions, which include TrustZone for Armv8-M. TrustZone introduces the concept of Secure and Non-Secure states, allowing developers to partition their software into secure and non-secure domains. This partitioning is crucial for…

ARM Assembly Integer-to-ASCII Conversion for System Output The core issue revolves around the inability to directly print integer values to the screen in ARM assembly. Instead of displaying the numeric value, the system outputs the ASCII representation of the integer, which is not the desired behavior. For example, when attempting to print the integer 99,…

Cortex-R8 AXI Unaligned Memory Access Behavior The Cortex-R8 processor, like many ARM cores, has specific requirements and behaviors when it comes to handling unaligned memory accesses. An unaligned memory access occurs when a data transfer operation targets an address that is not a multiple of the data size being accessed. For example, attempting to write…