Author: System on Chips

Cortex-M7 Unaligned Access Faults During LDM/STM/LDRD/STRD Operations The Cortex-M7 processor, based on the Armv7-M architecture, is a high-performance microcontroller core designed for embedded systems requiring significant computational power. One of its key features is the Memory Protection Unit (MPU) and the Tightly Coupled Memory (TCM) architecture, which enables low-latency access to critical data. However, the…

ARM Cortex-M3 Testbench Simulation Fails to Display "TEST PASSED" Statement When working with ARM Cortex-M3 testbenches, particularly in academic or research settings, one common issue that arises is the failure to display the "TEST PASSED" statement during simulation. This issue is often encountered when using simulation tools like Modelsim, where the simulation runs without errors…

ARM Cortex-M3 Hard Fault Triggered by USART Receive Interrupt The core issue revolves around a hard fault occurring in an STM32F101RF microcontroller during the execution of a USART receive interrupt service routine (ISR). The hard fault is triggered when the program attempts to read data from the USART Data Register (DR) within the ISR. The…

AHB5 Prot to AXI Cache Signal Mapping Challenges The mapping of AHB5 protocol signals to AXI cache attributes is a critical aspect of ensuring proper communication and data integrity between AHB and AXI-based systems. The AHB5 protocol, used in many ARM-based systems, defines a set of protection and cacheability signals (hprot) that must be correctly…

Understanding Unaligned AXI Transfers and Slave Support Requirements Unaligned transfers in the AXI (Advanced eXtensible Interface) protocol refer to data transactions where the starting address of a burst transfer is not aligned to the natural boundary of the data size being transferred. For example, a 32-bit (4-byte) transfer starting at address 0x01 is unaligned because…

AXI Slave Behavior with WR_STRB=0 and WVALID=1 The Advanced eXtensible Interface (AXI) protocol is a widely used on-chip communication standard for high-performance embedded systems. It defines a set of rules for data transfer between masters and slaves, ensuring efficient and reliable communication. One of the key signals in the AXI write data channel is WR_STRB…

ARM Cortex-M0+ Core Generality and Vendor-Specific Implementations The ARM Cortex-M0+ is a widely adopted 32-bit RISC processor core designed for embedded applications requiring low power consumption and high efficiency. While the Cortex-M0+ core itself is standardized by ARM, its implementation across different vendors introduces variability due to optional features, proprietary peripherals, and vendor-specific tooling. This…

ARM Cortex-M0+ Watchdog Timer Interrupt Handling Failure The issue at hand involves the Watchdog Timer (WDT) interrupt handler (WDT_IRQHandler) not being executed on an nRF51 microcontroller, which is based on the ARM Cortex-M0+ architecture. The user has configured the WDT to trigger an interrupt after a timeout period, but the interrupt handler is not being…

Identifying PMU Version and Features in ARM Cortex-A73 Processors The Performance Monitoring Unit (PMU) in ARMv8 architectures is a critical component for profiling and debugging system performance. However, determining the specific PMU version and features implemented in a particular ARM Cortex-A73 processor can be challenging due to the variability in ARMv8 implementations. The ARM Architecture…

VFMA Instruction Execution and Pipeline Behavior on ARM Cortex-M4 The ARM Cortex-M4 processor is a widely used microcontroller core that features a single-precision floating-point unit (FPU) and supports advanced SIMD instructions, including the Vector Fused Multiply-Accumulate (VFMA) instruction. The VFMA instruction is critical for high-performance signal processing, machine learning, and other compute-intensive tasks. However, understanding…