Author: System on Chips

ARM Cortex-R Atomic Double-Word Transfer Challenges Between ISR and Task The ARM Cortex-R series processors, known for their real-time capabilities and robust interrupt handling, often require careful consideration when implementing atomic operations across different execution contexts. One such scenario involves the use of LDREXD (Load Exclusive Double-Word) and STREXD (Store Exclusive Double-Word) instructions to facilitate…

ARM Cortex-M7 Vector Table Structure and Reset Handler Address Mismatch The ARM Cortex-M7 processor, like other Cortex-M series processors, relies on a vector table to manage exception handling and system initialization. The vector table is a critical data structure located at a specific memory address, typically starting at 0x00000000. Each entry in the vector table…

ARM TrustZone as a Hardware Security Foundation ARM TrustZone is a hardware-based security feature embedded within ARM processors, designed to create a secure environment for executing sensitive operations. It achieves this by partitioning the system into two distinct worlds: the Secure World and the Normal World. The Secure World is reserved for trusted software, such…

ARM Cortex-A Series EL2 Stage 2 Translation Faults and RCU Stalls The issue at hand involves a fault occurring during the configuration of Stage 2 address translation in the ARM Cortex-A series processor, specifically when attempting to set up a one-to-one mapping from Intermediate Physical Address (IPA) to Physical Address (PA) in the EL2 (Exception…

ARM Cortex-R Prefetch Abort During CP15 Cache Type Register Access Prefetch aborts in ARM Cortex-R processors are critical exceptions that occur when the processor attempts to execute an instruction from an invalid or inaccessible memory location. In this specific case, the prefetch abort is triggered during an attempt to access the Cache Type Register (CTR)…

ARM v8.6 Generic Timer Fixed 1GHz Frequency Overview The ARM v8.6 architecture introduces a significant change in the Generic Timer implementation, particularly regarding its fixed 1GHz frequency. This modification has raised questions about the flexibility of the timer’s frequency configuration and its implications for system design. The Generic Timer in ARM architectures is a critical…

ARM Cortex-M Migration Challenges from LPC2378 to Modern Alternatives The LPC2378, based on the ARM7TDMI-S core, has been a reliable workhorse for embedded systems for many years. However, with its obsolescence, developers are now faced with the challenge of migrating to a modern ARM Cortex-M-based microcontroller that offers long-term availability, improved performance, and enhanced features….

AHB-Lite DDR Interface Design and Burst Transaction Timing The Advanced High-performance Bus Lite (AHB-Lite) protocol is a simplified version of the AMBA AHB protocol, designed for systems with a single bus master. It is widely used in embedded systems, particularly for interfacing with memory subsystems such as DDR (Double Data Rate) memory. However, designing an…

Speculative Access in ARM Cortex-A7: Instruction Fetch vs. Data Access The ARM Cortex-A7 processor, a member of the ARMv7-A architecture family, is designed to optimize performance through techniques such as speculative execution. Speculative execution is a mechanism where the processor predicts the outcome of certain operations, such as branch instructions, and executes instructions ahead of…

Cortex-M55 Default Address Map and Boot Vector Placement The Cortex-M55 processor, like other ARM Cortex-M series processors, follows a predefined memory map that dictates how the processor interacts with memory and peripherals. This memory map is crucial for understanding where code, data, and peripherals are located, and it plays a significant role in the boot…