Cortex-M3 DesignStart Bitstream Incompatibility with Arty A7-100T FPGA The Cortex-M3 DesignStart FPGA-Xilinx edition package provides a pre-built bitstream for the Arty A7-35T FPGA board. However, users attempting to load this bitstream onto the Arty A7-100T FPGA board encounter an error: "Incorrect bitstream assigned to device. Bitfile is incompatible for this device." This issue arises because…
Cortex-A55 Performance Monitoring Unit (PMU) Counter Access Issues The Cortex-A55, a high-efficiency CPU in ARM’s DynamIQ family, incorporates a Performance Monitoring Unit (PMU) that provides critical insights into system performance through hardware counters. These counters track events such as cache misses, branch mispredictions, and instruction execution cycles, enabling developers to identify bottlenecks and optimize software….
Exclusive Access Failures in Multitasking Scenarios with LDREX/STREX The ARM architecture provides a mechanism for atomic operations through the use of Load-Exclusive (LDREX) and Store-Exclusive (STREX) instructions. These instructions are designed to facilitate synchronization in multiprocessing or multitasking environments by allowing a processor to attempt an atomic read-modify-write operation. However, the proper functioning of LDREX…
NSCFG Bit Functionality in S2CRn Register and Its Impact on Translation Table Walks The NSCFG (Non-Secure Configuration) bit in the S2CRn (Stream-to-Context Register n) register of the SMMUv2 (System Memory Management Unit version 2) architecture plays a critical role in determining the security state of translation table walks. When the NSCFG bit is set for…
NRF9160 CMSIS DSP Library Integration and Code Size Explosion When integrating the CMSIS DSP library into an NRF9160 project using the ARM Cortex-M33 core, developers often encounter significant code bloat. This issue arises when enabling multiple CMSIS DSP modules (e.g., FastMath, ComplexMath, Statistics, and Transform) via configuration flags in the Zephyr build system. The resulting…
ARM AArch64 Exception Vector Table Structure and IRQ Handler Placement The ARM AArch64 architecture defines a fixed exception vector table with specific offsets for different exception types, including IRQ (Interrupt Request) and FIQ (Fast Interrupt Request). Each vector in the table is 0x80 bytes in size, providing a limited space for the handler code. The…
NEON Intrinsics vs. Plain C XOR Performance on Cortex-A72 The performance discrepancy between NEON intrinsics and plain C code for XOR operations on the ARM Cortex-A72 processor is a nuanced issue that requires a deep dive into the architecture, instruction latency, and throughput characteristics. The Cortex-A72, found in the Raspberry Pi 4, is a high-performance…
Complex Number Operations and ARM NEON Intrinsics: Performance Challenges Complex number operations are a cornerstone of many signal processing algorithms, including Fast Fourier Transforms (FFT), digital filters, and matrix operations. ARM NEON intrinsics provide a powerful way to accelerate these operations on ARM Cortex-A and Cortex-M processors. However, leveraging NEON intrinsics for complex number operations,…
ARM Cortex-M33 DWT Watchpoint Configuration and DebugMon_Handler Challenges The ARM Cortex-M33 processor provides a powerful Debug Watchpoint and Trace (DWT) unit, which can be used to monitor memory accesses and trigger debug events. However, configuring the DWT watchpoints to accurately capture the instruction and memory address that triggered a debug event can be challenging. The…
Cortex-M7 Hardfaults Triggered by Unaligned Memory Access and Fault Status Register Analysis The Cortex-M7 microcontroller, specifically the STM32F722 variant, is experiencing random HardFaults that occur at various points in the code execution, including during stack initialization and within the main loop. The HardFaults are characterized by the FORCED bit in the HardFault Status Register (HFSR)…