Architectures and Processors

EL1 Permission Fault Triggered by EL0 Memory Access Configuration The issue revolves around a Memory Management Unit (MMU) configuration problem on the ARM Cortex-A53 processor, specifically when attempting to set up memory permissions that allow both Exception Level 1 (EL1) and Exception Level 0 (EL0) to access the same memory regions. The user has configured…

ARM AHB Endianness Configuration and Its Implications on System Design The Advanced High-performance Bus (AHB) is a critical component in ARM-based systems, providing a high-bandwidth, low-latency interface for connecting processors, memory controllers, and peripherals. One of the fundamental design considerations in AHB-based systems is the configuration of endianness, which determines the byte ordering of data…

AHB-Lite Protocol Signal Generation and Interconnection Challenges The AHB-Lite protocol, a subset of the Advanced Microcontroller Bus Architecture (AMBA), is widely used in embedded systems for its simplicity and efficiency in handling data transfers between masters and slaves. However, implementing the AHB-Lite protocol in a custom microcontroller design presents several challenges, particularly in understanding where…

Incorrect NVIC Configuration and Vector Table Handling on STM32F103 The core issue revolves around the misconfiguration of the Nested Vectored Interrupt Controller (NVIC) and improper handling of the vector table in an STM32F103 microcontroller. The user is attempting to configure Timer 6 (TIM6) interrupts but is encountering issues where the interrupts are not firing as…

ARM Cortex-A Series Cache Coherency During L2 Cache Maintenance Operations The ARM L2C-310 cache controller is a critical component in ARM Cortex-A series processors, responsible for managing the Level 2 (L2) cache. One of the key operations in the L2C-310 is the Cache Sync operation, which ensures that all pending cache maintenance operations are completed…

ARM Cortex-A9 R0 Register Corruption During Function Calls The issue at hand involves the corruption of the r0 register during subroutine calls on an ARM Cortex-A9 processor, specifically when the Memory Management Unit (MMU) is enabled. The problem manifests after approximately 100-200 cycles of a while loop, where a function A calls another function B…

Thumb-2 Instruction Set Confusion in ARM Cortex-M0/M0+/M1 Processors The Thumb-2 instruction set is a blend of 16-bit and 32-bit instructions designed to improve code density and performance in ARM processors. However, there is significant confusion regarding which instructions are supported across different ARM Cortex-M processors, particularly the Cortex-M0, Cortex-M0+, and Cortex-M1. These processors are based…

ARMv8 DBM Bit Functionality and Misconceptions The Dirty Bit Modifier (DBM) in ARMv8 architecture is a critical yet often misunderstood feature in the context of memory management and translation table descriptors. The DBM bit is part of the page or block descriptor in the translation tables used by the Memory Management Unit (MMU) to manage…

ARM Cortex L2C-310 Cache Controller Double Linefill Mechanism The ARM Cortex L2C-310 cache controller is a critical component in many ARM-based systems, responsible for managing data transfers between the L2 cache and external memory or L3 cache. One of its advanced features is the double linefill issuing mechanism, which can significantly impact system performance. This…

ARM Cortex-M Binary Size Calculation Challenges During Bootloader Copy When working with ARM Cortex-M microcontrollers, such as the STM32F103RB, developers often need to copy a bootloader from flash memory to RAM for execution. This process requires precise knowledge of the binary size of the bootloader to ensure accurate memory addressing and data transfer. However, determining…