ARM Cortex-M33 TrustZone Configuration for WiFi Peripheral Access The core issue revolves around the use of ARM TrustZone on the LPC55S69 microcontroller, specifically when attempting to configure and use a WiFi peripheral (such as the WiFi10Click board) from the Non-Secure (NS) world. The system operates correctly when the WiFi peripheral is initialized and managed from…
ARM Cortex-A72 KVM Guest Sync Exception with ESR_EL1 0x2000000: Cache Coherency and Dynamic Code Loading The issue at hand involves an ARM Cortex-A72-based Raspberry Pi 4B host running a KVM-accelerated OSv unikernel guest. The guest sporadically encounters a synchronous exception with the Exception Syndrome Register (ESR_EL1) value of 0x2000000, indicating an "Unknown Reason" exception. This…
ARM Cortex-A55 Unaligned Access Fault in EL3 with MMU Disabled When working with the ARM Cortex-A55 processor in the 64-bit execution state (AArch64) at Exception Level 3 (EL3), developers may encounter a data abort exception triggered by unaligned memory accesses, even when the MMU and caches are disabled. This issue arises when attempting to perform…
ARM TrustZone-M Architecture and RTOS Integration Requirements The ARM TrustZone-M architecture, introduced in ARMv8-M, is a security extension designed to provide hardware-enforced isolation between secure and non-secure states in microcontroller applications. This architecture is particularly relevant for embedded systems where security is paramount, such as IoT devices, automotive systems, and industrial control systems. TrustZone-M achieves…
GIC V2 Spurious Interrupt ID 1023 During UART Transmit Operations The ARM Generic Interrupt Controller (GIC) Version 2 is a widely used interrupt management system in embedded systems, particularly in ARM-based microcontrollers and processors. One of the challenges developers face when working with the GIC V2 is the occurrence of spurious interrupts, specifically Interrupt ID…
ARM Cortex-M4 Unaligned LDR Access Timing Discrepancies When performing unaligned memory accesses using the LDR instruction on an ARM Cortex-M4 processor, the expected behavior is that two memory read cycles are required to retrieve the data, regardless of whether the address is off by 1, 2, or 3 bytes from a word-aligned boundary. However, empirical…
ARM Cortex-M4 DAP Access Failures to PPB Trace Registers When working with ARM Cortex-M4 processors, particularly in debugging scenarios, accessing the Private Peripheral Bus (PPB) region through the Debug Access Port (DAP) can present significant challenges. The PPB region houses critical debug and trace components such as the Data Watchpoint and Trace (DWT), Instrumentation Trace…
ARM7TDMI Interrupt Latency and Serial Communication Stall at 200kHz Input Frequency The core issue revolves around the ARM7TDMI-based LPC2368 microcontroller experiencing interrupt overload when processing high-frequency input signals, leading to the stalling of the main program loop and subsequent failure of RS232 serial communication. The LPC2368 operates at a clock speed of 48MHz and utilizes…
ARM Cortex-M7 Program Execution Failure Post-Flash Programming The issue at hand involves an ARM Cortex-M7-based STM32F765 microcontroller where the program compiles and flashes successfully but fails to execute after power cycling or running without a debugger attached. The program runs correctly during a debugging session, indicating that the issue is not with the code logic…
Cortex-A57 MMU Initialization Crash During TLB Invalidation The issue at hand involves a Cortex-A57 core on the NVIDIA Jetson TX2 platform crashing during the initialization phase when the Memory Management Unit (MMU) is enabled. The crash occurs specifically when executing the TLBI ALLE2 instruction, which invalidates all TLB entries at Exception Level 2 (EL2). The…