ARM CMN600/CMN700 SF Size and Cache Performance Relationship The ARM CMN600 and CMN700 interconnect fabrics are critical components in modern System-on-Chip (SoC) designs, particularly when optimizing performance for multi-core ARM Cortex processors. The SF (System Cache) size configuration is a key parameter that directly impacts the performance of the system, especially when dealing with RN-F…
STM500 Channel ID Address Space Requirements and System Integration The integration of ARM CoreSight STM500 into a system-on-chip (SoC) design requires careful consideration of the address space allocation to support the required number of channel IDs. The STM500, a CoreSight System Trace Macrocell, is designed to provide high-bandwidth tracing capabilities for ARM-based systems. It supports…
ARMv8 Virtual Address Translation and Secure/Non-Secure EL1/0 Physical Address Mapping The ARMv8 architecture introduces a sophisticated memory management system that supports both secure and non-secure worlds, each with its own exception levels (ELs). A critical question arises when considering virtual address translation in this dual-world environment: Does the same virtual address in secure EL1/0 and…
AHB5 Narrow Burst Write Transfers and Strobe Calculation Challenges The Advanced High-performance Bus (AHB) protocol, particularly AHB5, is widely used in ARM-based systems for high-speed data transfers between masters and slaves. One of the critical aspects of AHB5 is the generation and interpretation of write strobes (HWSTRB) during narrow burst transfers, where the transfer size…
INTID Allocation and PE-Specific Interrupt Handling in ARM GIC-400 The ARM Generic Interrupt Controller (GIC) is a critical component in ARM-based systems, responsible for managing and prioritizing interrupts across multiple Processing Elements (PEs). The GIC-400, a specific implementation of the GIC architecture, provides a robust framework for handling interrupts, including Software Generated Interrupts (SGIs), Private…
HTRANS Behavior During AHB Error Response Cycles The Advanced High-performance Bus (AHB) protocol is a critical component of ARM-based systems, governing how data transfers occur between masters and slaves. One of the key signals in the AHB protocol is HTRANS, which indicates the type of transfer being performed. The HTRANS signal can take on several…
GIC-500 Initialization and Configuration Complexity in Bare-Metal Systems The integration of the ARM Cortex-A35 processor with the Generic Interrupt Controller 500 (GIC-500) in a bare-metal environment presents several challenges, particularly in the initialization and configuration of the GIC-500. The GIC-500 is a critical component in managing interrupts for multi-core systems, and its proper setup is…
ARMv8 Translation Fault Level 0 During TTBR0_EL1 Switch from Identity Mapping to User Process The core issue revolves around a translation fault level 0 occurring after switching the TTBR0_EL1 register from an identity mapping to a user process mapping in an ARMv8-based system, specifically on a Raspberry Pi 4B (BCM2711). The fault manifests when attempting…
ARMv8 MMU Translation Fault with 4KiB Granules in TTBR0_EL1 The ARMv8 architecture provides a sophisticated Memory Management Unit (MMU) that supports multiple translation table formats, including 4KiB, 16KiB, and 64KiB granule sizes. However, when configuring the MMU for user-space mappings using TTBR0_EL1, a common issue arises when attempting to use 4KiB blocks, resulting in a…
ARM Cortex-M0 vs. Cortex-M4 Performance and Instruction Set Challenges The BBC Micro:bit v1 and v2 present a unique challenge due to their vastly different hardware architectures. The v1 is powered by a Nordic nRF51822 microcontroller featuring a 16 MHz ARM Cortex-M0 core, while the v2 utilizes a Nordic nRF52833 with a 64 MHz ARM Cortex-M4…