Author: System on Chips

ARM Cortex-M4 Core and DMA Interaction Without Hbusreq and Hgrant Ports The ARM Cortex-M4 core, widely used in embedded systems, is designed for efficiency and low power consumption. However, unlike some other ARM cores, the Cortex-M4 does not include dedicated Hbusreq (bus request) and Hgrant (bus grant) ports for managing bus arbitration with other master…

Synchronous Abort During EL1 to EL0 Transition Due to MMU Misconfiguration The core issue revolves around a synchronous abort exception occurring when attempting to switch from Exception Level 1 (EL1) to Exception Level 0 (EL0) on an AARCH64-based system, specifically while testing a custom kernel on QEMU emulating a Raspberry Pi 3. The transition from…

ARM AHB5 Big-Endian Data Bus: MS and LS Byte Lane Significance The ARM AHB5 specification introduces a nuanced distinction in the representation of big-endian data buses, particularly with the inclusion of "Active[MS]" and "Active[LS]" in the byte lane descriptions. This addition, absent in the earlier AMBA 3 AHB-Lite specification, has raised questions about its significance…

ARM Cortex-A5 MMU and Cache Configuration for Performance Optimization Enabling the Memory Management Unit (MMU) and cache on an ARM Cortex-A5 processor is a critical step for optimizing system performance. However, improper configuration can lead to translation faults, memory access issues, and suboptimal performance. This guide addresses the challenges of configuring the MMU and cache,…

ARM Cortex-M23 MPU and TrustZone-M Interaction Overview The ARM Cortex-M23 processor, designed for embedded systems requiring robust security, integrates the Memory Protection Unit (MPU) and TrustZone-M technology. TrustZone-M partitions the system into secure and non-secure states, each with its own MPU instance: the Secure MPU (S_MPU) and the Non-Secure MPU (NS_MPU). The NS_MPU is responsible…

U-Boot’s Argument Passing Mechanism for Bare-Metal Applications When developing bare-metal applications for ARM-based systems, passing arguments from U-Boot to the application is a common requirement. U-Boot, as a bootloader, is responsible for loading the application binary into memory and transferring control to its entry point. However, unlike operating systems like Linux, bare-metal applications do not…

Cortex-R52 Clock Gate Bypass Impact on FPGA Timing Closure The Cortex-R52 is a high-performance, real-time processor designed for safety-critical applications, often integrated into complex System-on-Chip (SoC) designs. One of the challenges faced during FPGA prototyping of such SoCs is timing closure, particularly when dealing with clock gates embedded within the Cortex-R52. Clock gates are essential…

ARM Cortex-A FIQ Interrupts and Local Monitor Clearing During Semaphore Operations The ARM Cortex-A architecture, particularly when dealing with Fast Interrupt Requests (FIQ), can exhibit subtle but critical issues related to the local monitor’s behavior during semaphore operations. The local monitor is a hardware mechanism used to manage exclusive access to memory locations, ensuring atomicity…

ARM Cortex-A9 Boot Failure from Serial Flash on Renesas RZA1H Bootloader and Application Binary Configuration in Serial QSPI Flash The Renesas RZA1H microcontroller, based on the ARM Cortex-A9 architecture, is designed to support booting from various memory interfaces, including serial QSPI flash. In this scenario, the system is configured to boot from serial flash by…

ARM Processor and Ethernet MAC Configuration on AHB Bus In embedded systems utilizing the Advanced High-performance Bus (AHB) architecture, a common scenario involves multiple masters communicating with various slaves. One such configuration includes an ARM processor and an Ethernet MAC (Media Access Control) as masters on the AHB bus. The Ethernet MAC is responsible for…