Author: System on Chips

ARM Cortex-M4 Cache Coherency Problems During DMA Transfers The ARM architecture provides a set of synchronization primitives known as Load-Exclusive (LDREX) and Store-Exclusive (STREX) instructions. These instructions are crucial for implementing atomic operations in multi-threaded environments or when dealing with shared resources. However, the ARM Architecture Reference Manual for ARMv7-A and ARMv7-R explicitly states that…

PL230 DMA Controller Arbitration Cycle Consumption and Timing Analysis The PL230 DMA controller is a critical component in many ARM-based embedded systems, responsible for managing data transfers between peripherals and memory without CPU intervention. One of the key aspects of its operation is the arbitration process, which determines how the DMA controller allocates its resources…

Cache Coherency Behavior in ARM Cortex-A15 During Multi-Core Cache Flush and Invalidate Operations In ARM Cortex-A15-based systems, cache coherency is a critical aspect of ensuring data integrity and consistency across multiple cores. When two cores, such as Core 0 and Core 1, operate within the same inner shareable domain and access the same cache line,…

Cortex-R52 SPI Interrupt Routing to PEs Not Functioning GIC Configuration and Affinity Routing Issues The core issue revolves around the inability to route Shared Peripheral Interrupts (SPIs) to Processing Elements (PEs) other than core 0 in a Cortex-R52 multicore setup. The Generic Interrupt Controller (GIC) is configured to use affinity routing, as indicated by the…

ARM TrustZone Isolation and Secure Boot Limitations in Raspberry Pi ARM TrustZone is a hardware-based security feature embedded in ARM processors, designed to create isolated execution environments for secure and non-secure worlds. This isolation ensures that sensitive operations, such as cryptographic key management or secure boot processes, are protected from potential attacks. However, not all…

SPI4 Pin Configuration and DMA Initialization Failures on STM32 F411RE The STM32 F411RE microcontroller, based on the ARM Cortex-M4 architecture, is a powerful device widely used in embedded systems for its robust peripheral support, including multiple SPI interfaces. However, when transitioning from SPI1 to SPI4 on the STM32 F411RE Nucleo board, users often encounter issues…

ARMv8-A Secure vs Non-Secure State Detection in EL1 Kernel Code The ARMv8-A architecture introduces a robust security model that partitions the system into Secure and Non-Secure states. This separation is crucial for implementing TrustZone technology, which provides a secure environment for sensitive operations. However, when developing a Linux kernel that operates at Exception Level 1…

Understanding TAP ID Requirements for ARM Cortex-M Debugging When working with ARM Cortex-M microcontrollers, such as the HT32F52352 (Cortex-M0+), configuring the Test Access Port (TAP) is a critical step for enabling debugging and flashing capabilities. The TAP ID is a unique identifier that allows OpenOCD (Open On-Chip Debugger) to communicate with the microcontroller’s debug interface….

Cortex-R52 CoreMark Performance Discrepancy Between GCC and IAR Compilers The Cortex-R52 is a highly efficient real-time processor designed for safety-critical applications, offering a balance between performance and power efficiency. One of the key metrics used to evaluate the performance of such processors is CoreMark, a benchmark that measures the efficiency of a processor’s core in…

ARM Cortex Octa-Core Atomic Instruction Challenges Atomic instructions are fundamental to ensuring correct synchronization in multi-core systems, particularly in ARM architectures where concurrency and memory consistency are critical. In an octa-core system, the complexity of validating atomic instructions such as LDADD (Load and Add) and STADD (Store and Add) increases significantly due to the interplay…