Author: System on Chips

ARM Cortex-A9 and PL310 Cache Behavior During Non-Cacheable Writes The ARM Cortex-A9 processor, when paired with the PL310 L2 cache controller, exhibits complex behavior during non-cacheable writes, especially when the shared override bit is set. The core issue revolves around whether a non-cacheable write operation from an external master (such as a DMA controller) will…

Cortex-A53 Core Interference During High-Bandwidth Network Transfers The core issue revolves around an Asynchronous Multi-Processing (AMP) system implementation on an ARM Cortex-A53 processor, where multiple cores are tasked with running bare-metal and FreeRTOS-based applications concurrently. The system exhibits instability when FreeRTOS is introduced on Core 3 and Core 4, particularly during high-bandwidth network transfers between…

ARM Cortex-A53 FIQ and IRQ Timing Differences in AArch64 State The distinction between Fast Interrupt Requests (FIQ) and Interrupt Requests (IRQ) has been a topic of interest for embedded systems engineers working with ARM architectures. Historically, FIQs were designed to be faster than IRQs due to architectural optimizations in earlier ARM processors, such as the…

ARM Cortex ACE Protocol Cache Coherency Mechanisms The ARM ACE (AXI Coherency Extensions) protocol is designed to maintain cache coherency in multi-core systems, ensuring that all processors and agents have a consistent view of memory. The protocol introduces several transaction types, including ReadUnique, CleanUnique, and MakeUnique, which are critical for managing cache line states during…

ARM Cortex-A72 ACP Deadlock During GDMA and Prefetch Read Operations The ARM Cortex-A72 processor, when interfacing with the Accelerator Coherency Port (ACP) and a Generic Direct Memory Access (GDMA) controller, can encounter a deadlock scenario under specific conditions. This deadlock arises due to a combination of GDMA backpressure and speculative prefetch read operations from the…

ARM Cortex-A53 ALU Architecture and Parallel Execution Inquiry The ARM Cortex-A53 processor, part of the ARMv8-A architecture, is a highly efficient and power-optimized core designed for a wide range of applications, from mobile devices to embedded systems. One of the key components of the Cortex-A53 is its Arithmetic Logic Unit (ALU), which is responsible for…

ARMv8 CR52 TCM ECC Fault Injection Testing Overview The ARMv8 CR52 architecture, particularly when implemented in Renesas T2M series chips, incorporates Error Correction Code (ECC) functionality for both Cache and Tightly Coupled Memory (TCM). ECC is a critical feature for ensuring data integrity in safety-critical and high-reliability applications. It detects and corrects single-bit errors and…

MTB Configuration Challenges on Dual-Core Cortex-M33 (AN521) The Micro Trace Buffer (MTB) is a powerful debugging feature available in ARM Cortex-M series processors, enabling developers to trace instruction execution with minimal overhead. However, configuring the MTB on a dual-core Cortex-M33 system, such as the AN521 image running on the MPS2+ board, presents unique challenges. The…

TCM ECC Initialization Sequence and Enabling Timing The initialization of Tightly Coupled Memory (TCM) with Error Correction Code (ECC) on the ARM Cortex-R52 processor involves a critical sequence of steps that must be meticulously followed to ensure proper functionality. The Cortex-R52, being a real-time processor, relies heavily on TCM for low-latency and deterministic access to…

ARMv7-M Floating Point Extension and Coprocessor Access Control The ARMv7-M architecture incorporates a floating-point extension that relies on two coprocessors, CP10 and CP11, to manage floating-point operations. These coprocessors are controlled via the Coprocessor Access Control Register (CPACR), located at address 0xE000ED88. The CPACR register is critical for enabling or disabling access to the floating-point…