Coresight ETB RRD Register Access Errors During Trace Data Retrieval When working with ARM Cortex-A9 processors and utilizing Coresight Embedded Trace Buffer (ETB) for debugging and tracing, a common issue arises when attempting to read back trace data from the ETB RAM via the RRD (Read Response Data) register. The error message "Memory read error…
ARM Cortex-R52 Linux Porting Challenges Due to Missing MMU The ARM Cortex-R52 is a high-performance 32-bit processor designed for real-time embedded systems, particularly those requiring functional safety. Unlike its sibling, the Cortex-R82, the Cortex-R52 lacks a Memory Management Unit (MMU), which is a critical component for running standard Linux distributions. The absence of an MMU…
Cortex-A53 L1 Instruction Cache Behavior During Disabled State The Cortex-A53 processor, a widely used ARMv8-A architecture core, features separate L1 instruction and data caches. The L1 instruction cache is designed to store recently fetched instructions to reduce latency and improve performance. However, when the instruction cache is disabled, its behavior is not as straightforward as…
Understanding AXI5 Read Data Chunking and Signal Validity AXI5 (Advanced eXtensible Interface 5) is a protocol widely used in ARM-based systems for high-performance data transfers between components. One of its advanced features is Read Data Chunking (RDC), which allows a subordinate (slave) to return read data in chunks, aligned to 128-bit boundaries. This mechanism is…
TrustZone Address Space Controller (TZC) and AMBA5 CHI Interface Compatibility The integration of ARM’s TrustZone Address Space Controller (TZC) with the AMBA5 CHI (Coherent Hub Interface) presents a unique set of challenges, particularly when dealing with secure and non-secure transactions in a system-on-chip (SoC) design. The TZC-400, a well-known TrustZone Address Space Controller designed for…
ARM Cortex-A76AE Dual-Core Lockstep Mode and Cache System Interactions The ARM Cortex-A76AE processor, designed for safety-critical applications, features a Dual-Core Lockstep (DCLS) mode that enhances fault detection by running two cores in perfect synchronization. When DCLS is activated, the two cores execute the same instructions simultaneously, and their outputs are compared to detect discrepancies caused…
ARM Cortex-A17 Clock Speed Specification Mismatch The ARM Cortex-A17 is a mid-range processor core designed for high-performance embedded systems, often used in applications such as digital signage, smart TVs, and automotive infotainment systems. According to the official specifications, the Cortex-A17 is capable of operating at a maximum clock speed of 1.8GHz. However, in some implementations,…
ARM Cortex-M BusFault Exception on CPSIE I Due to Pending Interrupts When working with ARM Cortex-M microcontrollers, enabling interrupts using the CPSIE I instruction is a common operation. However, in some cases, enabling interrupts can lead to an immediate BusFault exception, often with an error code of 5 (IMPRECISERR) and a Program Counter (PC) value…
ARM Cortex-M Memory Access and Conditional Branch Optimization When working with ARM Cortex-M processors, efficiently testing the contents of a 16-bit memory cell for zero is a common task that can be optimized for both performance and code size. The ARM instruction set provides several mechanisms to achieve this, but understanding the nuances of memory…
ARM Cortex-M4 Cache Coherency Problems During DMA Transfers The ARM Cortex-M4 processor, renowned for its efficiency in embedded systems, often encounters cache coherency issues when Direct Memory Access (DMA) transfers are involved. These problems typically manifest as data inconsistencies between the processor’s cache and the main memory, leading to erroneous program behavior or system crashes….