ARM Juno Board Android 10 Upgrade Challenges The ARM Juno board, a development platform widely used for testing and prototyping on ARM architectures, presents unique challenges when upgrading from Android 9 to Android 10. The primary issue revolves around the compatibility of the existing Juno SDK, which is based on Android 9, with the newer…
Understanding the DHCSR Register and C_DEBUGEN Bit Behavior The Debug Halting Control and Status Register (DHCSR) is a critical component in ARM Cortex-M processors, primarily used for controlling and monitoring the debug state of the processor. One of its key bits is the C_DEBUGEN bit, which enables or disables the debug functionality. The issue at…
ARM Cortex-M Synchronous Exception Handling in QEMU Synchronous exceptions in ARM Cortex-M processors occur when the processor encounters an issue that prevents the normal execution of an instruction. These exceptions are precise, meaning they are triggered immediately after the offending instruction is executed, and the processor state is well-defined at the point of the exception….
ARM TrustZone and Secure Enclave Implementation Challenges on ARMv8-A ARM TrustZone is a hardware-based security feature embedded in ARM processors, designed to create a secure environment for executing sensitive code and handling confidential data. TrustZone achieves this by dividing the system into two worlds: the Secure World and the Normal World. The Secure World operates…
ARMv8-A Translation Table APTable Permission Faults in Secure World Implementations Understanding the APTable Permission Mechanism in ARMv8-A Translation Tables The ARMv8-A architecture employs a multi-level translation table system to manage virtual-to-physical address mappings and access permissions. The translation tables are hierarchical, with each level responsible for a portion of the virtual address space. The Access…
ARM Cortex-M0 Parallel Flash Memory Integration Challenges Integrating external parallel flash memory with an ARM Cortex-M0 microcontroller involves addressing several hardware and software interface challenges. The Cortex-M0, being a 32-bit microcontroller, often requires interfacing with 16-bit or 8-bit parallel flash memories, which introduces complexities related to byte enable signals, address mapping, and timing synchronization. The…
ARM Cortex-M4 Dynamic Loading HardFault Due to Uninitialized R9 Register The core issue revolves around dynamically loading position-independent code (PIC) into RAM on an ARM Cortex-M4 microcontroller and executing it. The problem manifests as a HardFault when the dynamically loaded function attempts to execute a blx r1 instruction, where r1 is uninitialized or incorrectly set…
RTOS Memory Protection Mechanisms on Cortex-M Processors Real-Time Operating Systems (RTOS) on ARM Cortex-M processors often rely on the Memory Protection Unit (MPU) to enforce memory protection between tasks. The Cortex-M series, unlike Cortex-A or Cortex-R, does not include a Memory Management Unit (MMU), making the MPU the primary mechanism for memory protection. The MPU…
Understanding STM32H747 Dual-Core Architecture and GCC Compilation The STM32H747 microcontroller, featuring a Cortex-M7 and Cortex-M4 core, presents a unique set of challenges for developers, particularly when using the GCC toolchain. The dual-core architecture requires a nuanced understanding of both hardware and software interactions to ensure efficient and reliable operation. The Cortex-M7, with its higher clock…
AXI Transaction ID Collision in Multi-Master Systems In advanced ARM-based systems, the Advanced eXtensible Interface (AXI) protocol is widely used for high-performance communication between masters (such as CPUs, GPUs, or DMAs) and slaves (such as memory controllers or peripherals). A critical aspect of AXI is the use of transaction IDs to manage out-of-order transactions and…