Author: System on Chips

Timer0 Configuration and Expected Behavior The core issue revolves around the Timer0 peripheral on the LPC1768 microcontroller, which is based on the ARM Cortex-M3 architecture. The Timer0 is configured with a master clock source of 12 MHz, which is multiplied to a core clock (CCLK) of 100 MHz using the Phase-Locked Loop (PLL). The peripheral…

ARM Cortex-A7 Cache Line Size Discrepancy in ARMv7-A Programmer’s Guide The ARM Cortex-A7 processor, a member of the ARMv7-A architecture family, is widely used in embedded systems for its balance of performance and power efficiency. A critical aspect of its performance is the cache architecture, which directly impacts memory access latency and overall system throughput….

ARMv8-M Security State Determination via CPUID_NS Register The ARMv8-M architecture introduces TrustZone technology, which partitions the system into Secure and Non-secure states. This partitioning is crucial for ensuring that sensitive code and data are protected from unauthorized access. A common question that arises when working with ARMv8-M is how to determine the current security state…

ARM Cortex-M33 Stack Pointer (SP) Modification Issues in Handler Mode Understanding the Context: SP Modification in Handler Mode for Fault Recovery In embedded systems, particularly those utilizing ARM Cortex-M series processors, the Stack Pointer (SP) plays a critical role in managing function calls, local variables, and interrupt handling. The ARM Cortex-M33, being a member of…

ARM Cortex-M Monitor Mode Debugging: Overview and Use Cases Monitor Mode Debugging (MMD) is a specialized debugging technique available on ARM Cortex-M processors that allows developers to debug applications without halting the core. Unlike traditional halting debug modes, which pause the processor entirely, MMD enables real-time inspection and modification of registers, memory, and peripherals while…

ARM NEON Vector Arrangement Specifiers: .16b and .8b Explained The arrangement specifiers in ARM assembly language, particularly in the context of NEON instructions, are critical for defining how vector registers are interpreted and manipulated. These specifiers, such as .16b and .8b, dictate the granularity and structure of data within the NEON registers, which are 128-bit…

ARM Cortex-M3 Tach Signal Capture and LED Control Issues on LPC1768 The LPC1768 microcontroller, based on the ARM Cortex-M3 architecture, is a popular choice for embedded systems due to its robust peripheral set and ease of use. However, interfacing with external components such as DC fans and LEDs can present challenges, particularly when dealing with…

ARM Cortex-A8 Branch Prediction Mechanism and Spectre-v1 Vulnerability The ARM Cortex-A8 processor, like many modern CPUs, employs branch prediction to optimize instruction execution by predicting the outcome of conditional branches. This mechanism is critical for maintaining high performance in pipelined architectures, as it reduces pipeline stalls caused by branch instructions. However, this same mechanism can…

ARMv7 Generic Timer and System Counter Initialization Issues The ARMv7 architecture includes a Generic Timer that relies on a System Counter to function correctly. The Generic Timer is a critical component for timekeeping, scheduling, and synchronization in ARM-based systems. However, a common issue arises when the Generic Timer does not start ticking, even after proper…

Cortex-A53 Core Synchronization Failure During Bare-Metal Debugging in DS-5 When debugging a system-on-chip (SoC) with dual Cortex-A53 cores using ARM’s DS-5 tool, a common issue arises where only one core can be debugged successfully in bare-metal mode. The second core fails to operate normally when both cores are debugged simultaneously. This issue is often rooted…