Serial Port 1 Interrupt Configuration and Initialization Issues The core issue revolves around the inability to trigger the Serial Port 1 interrupt on an 8051 microcontroller, despite seemingly correct initialization and configuration. The primary symptom is that the interrupt service routine (ISR) for Serial Port 1 does not execute, even when data is sent to…
CNTPCT_EL0 Timer Desynchronization Across Processing Elements (PEs) The ARM architecture, particularly in multi-core systems, relies heavily on synchronized timers for accurate timing and coordination between different Processing Elements (PEs). The CNTPCT_EL0 register, which holds the physical counter value, is a critical component in this synchronization. However, discrepancies in CNTPCT_EL0 values across PEs within the same…
Understanding ARMv8-A Execution States and Android OS Constraints The ARMv8-A architecture introduces a significant evolution in the ARM ecosystem by supporting two execution states: AArch32 and AArch64. AArch32 is the 32-bit execution state, which is backward compatible with ARMv7-A, while AArch64 is the 64-bit execution state, offering a new instruction set and architectural features. Android…
ARM TrustZone Development Challenges for Cortex-A Series Beginners Developing trusted applications for mobile and embedded devices using ARM Cortex-A series processors and TrustZone technology can be a daunting task, especially for beginners. The Cortex-A series, unlike the Cortex-M series, offers a more complex environment due to its advanced features and capabilities. TrustZone technology provides a…
Azure Sphere and ARM PSA: Understanding Their Security Architectures Azure Sphere and ARM’s Platform Security Architecture (PSA) are two prominent security frameworks designed to enhance the security of embedded systems. Azure Sphere, developed by Microsoft, is a comprehensive solution that includes hardware, software, and cloud components to secure IoT devices. It incorporates the Pluton security…
Prefetch Abort During Flash Erase with Misleading ECC Error Indication The issue at hand involves an ARM Cortex-R4F processor (specifically the TI TMS570LS3137) experiencing a prefetch abort during flash erase operations. The prefetch abort is accompanied by misleading indications of a Synchronous Parity/ECC error in the Instruction Fault Status Register (IFSR), despite the fact that…
CNTPCT_EL0 System Timer Continuity During Core Resets The behavior of the CNTPCT_EL0 system timer during core resets in ARM Cortex-A35 processors is a critical consideration for developers working on multi-core systems, particularly in scenarios where one Processing Element (PE) is reset while others remain operational. CNTPCT_EL0, the Counter-timer Physical Count register, is a 64-bit register…
PendSV Exception Banking and Secure State Context Switching The PendSV (Pendable Service Call) exception in ARMv8-M architecture is a critical mechanism for implementing context switching in real-time operating systems (RTOS). It is particularly useful for deferring context switching until higher-priority interrupts have completed, ensuring deterministic behavior in embedded systems. However, the introduction of the ARMv8-M…
ARM926EJ-S Illegal Instruction Error During Program Execution The ARM926EJ-S processor, a member of the ARM9 family, is a widely used embedded processor known for its balance of performance and power efficiency. However, when running a simple "Hello World" program on a Linux-based system with kernel version 2.6.28, the program crashes with an "Illegal Instruction" error….
ARMv8.5 E0PD Mechanism and Its Role in Meltdown Mitigation The ARMv8.5 architecture introduces the E0PD (Exception Level 0 Prevention of Data access) mechanism, which is designed to alter the timing of faults in a way that can potentially mitigate certain types of speculative execution attacks, such as Meltdown. The Meltdown attack exploits a vulnerability in…