GIC-600 Distributor Communication via AXI-Stream in Multichip Configurations The ARM Generic Interrupt Controller 600 (GIC-600) is a highly scalable interrupt controller designed for complex systems, including multichip configurations. In such systems, multiple GIC-600 Distributors must communicate with each other to ensure coherent interrupt handling across chips. The GIC-600 Technical Reference Manual specifies that this communication…
ARM CPU with ASIC AES Encryption: Architectural Overview and Use Case The concept of integrating an ASIC-based AES encryption engine directly into the data bus of an ARM CPU is an intriguing architectural proposal. The primary goal is to create a system where all data flowing through the CPU’s data bus is transparently encrypted before…
ARM Cortex-A76 Cache Behavior During Matrix Column Reads with Prefetching The observed performance degradation despite an improved L2 cache hit rate on the ARM Cortex-A76 processor, as seen in the matrix column read program, is a complex issue that involves multiple layers of cache hierarchy and prefetching mechanisms. The Cortex-A76, used in the Raspberry Pi…
Secure and Non-Secure MPU Configuration Leading to MemManage Fault Escalation The issue at hand involves a Cortex-M33 microcontroller unit (MCU) running FreeRTOS-MPU in the non-secure world with the Non-Secure Memory Protection Unit (MPU_NS) enabled, while executing trusted code in the secure world with the Secure Memory Protection Unit (MPU_S) disabled. The problem manifests when the…
ARM Cortex-ETM Trace Configuration and ATVALID Signal Failure The ARM Embedded Trace Macrocell (ETM) is a critical component for real-time instruction tracing in ARM-based systems, enabling developers to capture and analyze the execution flow of their software. The ATVALID signal, which indicates that the trace unit is ready to output valid trace data, is a…
Activation Control, Data Capture, and Secure Operation Requirements When designing an ASIC with functionalities such as activation control, data capture, data aggregation, operational feedback, data retrieval, and secure operation, the choice of microcontroller unit (MCU) is critical. The ARM Cortex-M3, Cortex-M4, and Cortex-M33 are all viable candidates, but each has distinct architectural features that make…
Enabling CCR.DIV_0_TRP and Resulting Exceptions The Configuration Control Register (CCR) in ARM Cortex-M processors is a critical register that controls various system behaviors, including the handling of specific faults such as divide-by-zero errors. The CCR.DIV_0_TRP bit, when enabled, configures the processor to trap divide-by-zero operations, allowing developers to handle such errors programmatically rather than allowing…
SYST_CVR Register Access Violation in User Mode on ARM Cortex-M33 The ARM Cortex-M33 processor, part of the ARMv8-M architecture, is designed with a robust security model that includes privilege levels to separate user code from system-level operations. One of the key features of this architecture is the ability to restrict access to certain registers and…
ARM Cortex-M55 PMU Cycle Counter Returning Zero During Code Execution The Performance Monitoring Unit (PMU) in the ARM Cortex-M55 processor is a critical tool for measuring CPU cycles during code execution. However, a common issue arises when the PMU cycle counter returns zero, even though the code compiles and runs without errors. This problem can…
Cortex-R52+ Floating-Point Register Corruption in ISRs The Cortex-R52+ processor, based on the Armv8-R AArch32 architecture, exhibits unexpected behavior when floating-point calculations are performed within interrupt service routines (ISRs). Specifically, floating-point register values may become corrupted or inconsistent across multiple ISR invocations. This issue arises due to the architecture’s design, which does not automatically save and…