Architectures and Processors

FMC Interface Initialization and SRAM Access Issues on STM32H743 The STM32H743 microcontroller features a Flexible Memory Controller (FMC) that enables interfacing with external memory devices such as SRAM, SDRAM, and NOR Flash. However, users often encounter issues when attempting to read from external SRAM using the FMC interface. A common symptom is that the FMC…

ARM Cortex-M0 Vector Table Remapping Limitations The ARM Cortex-M0 processor, being one of the most widely used 32-bit microcontrollers in embedded systems, has a fixed memory map that includes the vector table located at the beginning of the memory space. The vector table is a critical component of the Cortex-M0 architecture, as it contains the…

EL2 to EL1 Transition with Instruction Prefetch Abort on ERET The core issue revolves around the failure to transition from Exception Level 2 (EL2) to Exception Level 1 (EL1) in an ARMv8-A architecture. The transition is attempted by setting up the necessary system registers, including sctlr_el1, spsr_el2, elr_el2, and hcr_el2, followed by an eret instruction….

ARM Cortex-A Series Secondary Core Initialization and Wake-Up Mechanisms In ARM-based multiprocessor systems, the initialization and wake-up of secondary cores from the primary core is a critical process that involves setting the Program Counter (PC) and ensuring proper synchronization. The ARM architecture, particularly in the Cortex-A series, provides several mechanisms to achieve this, but the…

ARM Cortex-M3 Clock Frequency Instability During Function Execution The core issue revolves around the STM32F103C8T6 microcontroller, which exhibits inconsistent delay timing when the CountDigit() function is executed. Specifically, the Delay(1000) function, which is expected to produce a 1-second delay, instead produces a delay of approximately 0.7 seconds after CountDigit() is called. This behavior suggests that…

Accessing PSTATE.nRW to Determine CPU Run State The Cortex-A57 processor, part of the ARMv8-A architecture, supports both AArch64 and AArch32 execution states. The execution state determines whether the processor is operating in 64-bit or 32-bit mode. The PSTATE.nRW bit is a critical register that indicates the current execution state of the CPU. When PSTATE.nRW is…

ARM Cortex-A9 to Cortex-A53 Program Execution Compatibility The transition from an ARM Cortex-A9 to an ARM Cortex-A53 processor involves several architectural considerations that can impact the execution of existing programs. The Cortex-A9, based on the ARMv7-A architecture, and the Cortex-A53, based on the ARMv8-A architecture, share some similarities but also have significant differences that must…

Cortex-M3 Frequency Limitations in 0.18 TSMC Process Nodes The Cortex-M3 processor, a widely used ARM core in embedded systems, is known for its balance of performance, power efficiency, and cost-effectiveness. However, determining its maximum operating frequency in a specific process node, such as TSMC’s 0.18µm technology, involves a complex interplay of factors. These factors include…

Cortex-R5 Divide-by-Zero Exception Handling Mechanism The Cortex-R5 processor, like many ARM cores, provides a mechanism to handle arithmetic exceptions such as divide-by-zero operations. This is controlled via the System Control Register (SCTLR), specifically the DZ (Divide-by-Zero) bit. When the DZ bit is set, the processor generates an Undefined Instruction exception upon encountering a divide-by-zero operation….

GIC-500 Stuck State After Cortex-A53 Software Reset The core issue revolves around the Generic Interrupt Controller (GIC-500) in the Armada 3720 SOC entering a stuck state after a software-initiated reset of the Cortex-A53 cores. The Cortex-M3 secure coprocessor is tasked with orchestrating the reset sequence, which includes resetting the Cortex-A53 cores, peripherals, and the GIC-500….