ARMv8-A Real-Time Counter Requirements and Challenges In ARMv8-A architectures, particularly in multicore systems like the Xilinx RFSoC with four Cortex-A53 cores, achieving a low-overhead, high-resolution real-time counter that is consistent across all cores and accessible from user-level code (EL0) is a non-trivial task. The primary requirement is to read a counter with a resolution of…
ARM Cortex-A Bare Metal I/O Architecture and Documentation Gaps When working with ARM Cortex-A processors in a bare-metal environment, one of the most significant challenges is understanding and implementing I/O operations without the abstraction layers provided by an operating system. The Cortex-A series, known for its application-grade performance, is typically integrated into complex System-on-Chip (SoC)…
ARM Cortex-M7 Cache Coherency Challenges with Peripheral DMA Transfers The ARM Cortex-M7 processor, with its advanced features like data cache and high-performance memory system, is widely used in embedded systems requiring efficient data processing. However, these features can introduce complexities when interfacing with peripheral DMA engines, such as the Ethernet GMAC (Gigabit Media Access Controller)….
ARM Address Size Faults in Long-Descriptor Translation Table Formats Address size faults in ARM architectures occur when the translation of a virtual address to a physical address encounters an inconsistency or violation in the address size constraints defined by the Long-descriptor translation table format. Specifically, the fault is triggered when bits [47:40] of a descriptor…
UART Initialization and Configuration Issues on Nuvoton Nano100 Series The core issue revolves around the failure to receive any data on the UART serial terminal despite the code compiling successfully. The user is attempting to configure and use UART0 and UART1 on an ARM Cortex-M0 microcontroller from the Nuvoton Nano100 Series. The code includes clock…
ARMv8 SVE Contiguous Non-Fault Load Instructions: Key Concepts and Use Cases The ARMv8 Scalable Vector Extension (SVE) introduces a powerful set of instructions designed to enhance performance in data-parallel workloads. Among these, the contiguous non-fault load instructions (LDNF) stand out as a specialized tool for handling memory operations in scenarios where fault tolerance and predictable…
Cortex-R5 Outperforming Cortex-A9: Clock Cycles vs Execution Time Mismatch The observed performance discrepancy between the ARM Cortex-R5 and Cortex-A9 processors, where the Cortex-R5 completes a computation in half the time despite using significantly more clock cycles, is a multifaceted issue rooted in architectural differences, memory subsystem configurations, and potential misconfigurations in the Cortex-A9 setup. The…
Cortex-M4 Processor State Preservation Requirements During Power-Down The Cortex-M4 processor, like many ARM cores, is designed for low-power applications where power-down and resume functionality is critical. When powering down the Cortex-M4 while retaining system RAM, the processor state must be saved to ensure a seamless restoration upon resumption. This involves preserving not only the core…
Cortex-A17 Cache Flush Latency: Understanding the Performance Bottleneck The flush_cache_all() function on the Cortex-A17 core, operating at 1.25 GHz with a 32 KB I-cache, 32 KB D-cache, and 256 KB L2 cache, is reported to consume over 200 microseconds. This latency is significant, especially in real-time or performance-critical applications where cache maintenance operations must be…
ARM Cortex-M Toolchain Confusion: GNU-ARM-GCC vs. ARM-None-EABI-GCC The ARM Cortex-M series of microcontrollers is widely used in embedded systems due to its efficiency, low power consumption, and robust performance. However, one of the most common sources of confusion for developers new to the ARM ecosystem is the variety of toolchains available for compiling and debugging…