APB Slave Selection Mechanism and Address Decoding in Single-Master Systems In an Advanced Peripheral Bus (APB) system with a single master and multiple slaves, the master communicates with one slave at a time. The selection of the slave is determined by the PSEL (Peripheral Select) signal, which is generated based on address decoding. The PSEL…
ARM Cortex-A53 STUR Instruction and Synchronous Exception Overview The ARM Cortex-A53 processor, operating in AArch64 mode, is a widely used 64-bit ARM core known for its efficiency and performance in embedded systems. One of the instructions available in the A64 instruction set is the STUR (Store Register Unscaled) instruction, which is used to store a…
Understanding Secure and Non-Secure CONTROL Register Banked Fields in Cortex-M33 The ARM Cortex-M33 processor, which incorporates TrustZone-M technology, introduces a dual-world execution environment: Secure and Non-Secure. This separation is critical for implementing robust security architectures in embedded systems. The CONTROL register in the Cortex-M33 is one of the key registers that is banked between these…
Cortex-R52+ Undefined Exception Triggered Post-Debug Exception The Cortex-R52+ processor is a high-performance, real-time capable core designed for safety-critical applications. It is common to encounter complex exception handling scenarios in such systems, especially when debugging is involved. In this case, the processor enters an undefined exception immediately after a debug exception. The undefined exception is triggered…
AXI4 Initiator 32-bit to APB 8-bit Target Data Transfer Challenges When designing an AXI4 to APB bridge, one of the most intricate challenges arises when dealing with data width mismatches between the AXI4 initiator and the APB target. In this scenario, the AXI4 initiator has a 32-bit data width, while the APB target operates with…
APB3 Master and APB4/APB5 Slave Interoperability Challenges The Advanced Peripheral Bus (APB) is a key component of the ARM Advanced Microcontroller Bus Architecture (AMBA) family, designed for low-power, low-complexity peripheral interfacing. A common question arises when designing systems with APB: Can an APB3 master interface communicate effectively with an APB4 or APB5 slave? The short…
ARM Cortex-A725 CASAL Instruction Fault in EL1 with MMU Enabled The issue revolves around a data abort exception (0x96000035) triggered during the execution of the CASAL (Compare and Swap Atomic Local) instruction on an ARM Cortex-A725 processor. The exception occurs in EL1 (Exception Level 1) with the MMU (Memory Management Unit) enabled, and the fault…
ARM Cortex-R52+ Data Abort Triggered by CPSR Write Operation The Cortex-R52+ processor is a high-performance, real-time capable core designed for safety-critical applications. It is common to encounter complex hardware-software interaction issues when working with such architectures, especially when dealing with low-level register manipulations. One such issue arises when executing the MSR CPSR_cx, #0x1F instruction, which…
FIQ Exception with INTID 1023 During Mixed IRQ and FIQ Handling The ARM Cortex-R52 processor, when configured with the Generic Interrupt Controller (GIC) version 3, can encounter a scenario where a Fast Interrupt Request (FIQ) exception is taken, but the Interrupt Acknowledge Register (ICC_IAR0) returns an Interrupt ID (INTID) of 1023. This value is a…
ARM Cortex-A7 and Cortex-A9 Processors with Gigabit Ethernet: Key Considerations When selecting an ARM processor with Gigabit Ethernet support, several factors must be considered to ensure the chosen processor meets the requirements of the intended application. The primary considerations include the processor’s architecture, the availability of a free Integrated Development Environment (IDE), and the overall…