High CPU Load on ARM Cortex-M7 Compared to Cortex-M4 Despite Higher Clock Speed The core issue revolves around an ARM Cortex-M7 microcontroller (CYT4BFBCJE) running at 160 MHz exhibiting a significantly higher CPU load (95%) compared to an ARM Cortex-M4 microcontroller (CYT2B9X) running at 80 MHz, which only shows a 25% CPU load. Both systems are…
Cortex-A55 Boot Process and AArch32-to-AArch64 Transition Challenges The Cortex-A55 is a highly efficient 64-bit ARM processor that supports both AArch32 and AArch64 execution states. However, transitioning from AArch32 to AArch64 during the boot process can be complex, particularly when the system defaults to AArch32 at reset. This issue arises in scenarios where the BootROM and…
ARM Cortex-M3 Limitations for Android OS Installation The ARM Cortex-M3 processor, such as the one found in the NXP LPC1788 microcontroller, is a highly efficient and power-optimized processor designed for real-time embedded applications. However, its architecture presents significant limitations when attempting to run a complex operating system like Android. The primary issue stems from the…
Cortex-M7 Frame Pointer Setup and Stack Dependency in Function Prologue The Cortex-M7 microcontroller, with its superscalar 6-stage pipeline, introduces unique considerations for stack management and frame pointer usage, especially when debugging HardFaults. In the provided code, the function prologue for I2cHW::endTransmission() demonstrates a sequence of operations that manipulate the stack pointer (SP) and frame pointer…
Kernel Boot Delays During Root Filesystem Mounting and Initialization The issue at hand involves a significant delay during the kernel boot process on an ARM Cortex-A55-based Rockchip RK3568 platform when booting from an SD card. The delay manifests primarily during the mounting of the root filesystem and the subsequent initialization of system services. The kernel…
Secure World Control of Non-Secure MPU in ARM Cortex-M33 The ARM Cortex-M33 processor, part of the ARMv8-M architecture, introduces a robust security model through its TrustZone technology. This model divides the system into Secure and Non-Secure worlds, each with its own Memory Protection Unit (MPU). The Non-Secure MPU (NS-MPU) is typically accessible from both worlds,…
ARM Cortex-M0+ SWD Interface Lockout During GPIO Misconfiguration The STM32G041C8T6 microcontroller, based on the ARM Cortex-M0+ core, is experiencing a complete lockout from the SWD (Serial Wire Debug) interface, preventing further flashing or erasing of the device. This issue arises after a firmware implementation where GPIO pins were misconfigured, specifically involving PA8 and PB2. The…
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…
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…
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…