Author: System on Chips

ARM Cortex-A53 GDB "g Packet" Error During Debugging When attempting to debug an ARM Cortex-A53 target using the aarch64-none-linux-gnu-gdb debugger on a Linux platform, users may encounter a failure to load the register view. This issue manifests as a "g packet" error, which indicates that the debugger is unable to retrieve the target’s register state….

Dual Stack Pointers and Privilege Levels in ARM Cortex-M Microcontrollers The ARM Cortex-M architecture, particularly in microcontrollers without a Memory Management Unit (MMU), employs a dual stack pointer mechanism alongside privilege levels to enhance system reliability, security, and efficiency. This architectural feature is crucial for embedded systems where resource constraints and real-time performance are paramount….

Cortex-R5F PreFetch Exception Handling and Debugger Interference When working with the Cortex-R5F processor, implementing breakpoints and handling exceptions can be particularly challenging, especially when external debuggers are involved. The core issue revolves around the behavior of the PreFetch Exception and the interaction between the processor’s debug modes—specifically, the transition from Monitor debug-mode to Halting debug-mode…

ARM Cortex-A53 CPSR Corruption After Exception Return from EL3 to EL1 The ARM Cortex-A53 processor, part of the ARMv8-A architecture, is designed to handle exceptions and interrupts across multiple exception levels (ELs). A critical issue arises when returning from an exception in EL3 (Secure Monitor) to EL1 (OS Kernel), where the CPSR (Current Program Status…

Cortex-R52 AXI Transfer Restrictions and Cache Line Boundary Alignment The ARM Cortex-R52 processor, designed for real-time and safety-critical applications, imposes specific restrictions on AXI (Advanced eXtensible Interface) transfers, particularly concerning cache line boundary alignment. According to the Cortex-R52 Technical Reference Manual (TRM), all WRAP bursts fetch a complete cache line starting with the critical word…

ARM Cortex-R52 Interrupt Vector Offset Configuration Challenges The ARM Cortex-R52, a real-time processor designed for safety-critical applications, presents unique challenges when configuring the interrupt vector table offset. Unlike the Cortex-M series, which utilizes the Vector Table Offset Register (VTOR) for straightforward interrupt vector table relocation, the Cortex-R52 employs a different mechanism due to its more…

Cortex-M0+ SWD Debug Protocol Implementation Challenges Developing a Serial Wire Debug (SWD) debugger for the ARM Cortex-M0+ processor, particularly when targeting an FPGA-based implementation, presents several technical challenges. The SWD protocol, while relatively simple in its basic form, requires a deep understanding of the ARM Debug Interface Architecture and the Cortex-M0+ core’s debug capabilities. The…

ARM Cortex-R4 Interrupt Handling Failure with VIC and ICUA Integration The ARM Cortex-R4 is a high-performance processor designed for real-time applications, often integrated with complex interrupt controllers like the Vector Interrupt Controller (VIC) and ICUA (Interrupt Control Unit A) in systems such as Renesas Electronics’ RZ/T1. In this scenario, the Cortex-R4 fails to handle interrupts…

ARM Cortex-A IERRR Bit Set Persistently Before and After GIC Initialization The IERRR (Internal Error Reporting Register) bit being set persistently before and after Generic Interrupt Controller (GIC) initialization on an ARM Cortex-A processor is a critical issue that can indicate underlying hardware or software problems. The IERRR bit is part of the processor’s error…

ARM Cortex-M7 ITCMERR Signal Protocol and CPU Behavior The ITCMERR signal in the ARM Cortex-M7 processor is a critical part of the Instruction Tightly Coupled Memory (ITCM) protocol, which is used to indicate errors during instruction fetches from the ITCM. When the ITCMERR signal is set HIGH, the CPU must handle the error condition in…