Architectures and Processors

ARM Cortex-M4 16-bit Memory Read Behavior on 32-bit Data Bus When designing embedded systems with ARM Cortex-M4 processors, one common scenario involves interfacing a 16-bit memory chip with a 32-bit data bus. This configuration is often used to optimize cost and power consumption while maintaining sufficient performance for many applications. However, this setup can lead…

Xen Bootloader Configuration and Dom0 Kernel Image Specification The core issue revolves around the Xen hypervisor failing to locate and load the Dom0 kernel image on the ARM Juno r2 board. When Xen is launched, it throws the error "No Dom0 kernel image specified," indicating that the bootloader configuration or the kernel image itself is…

ARM Cortex-M33 Secure-Non-Secure Transition Failure During Debugging The core issue revolves around the inability to debug the non-secure (NS) image on the ARM FVP_MPS2_AEMv8M platform, specifically when attempting to step through the non-secure code after setting a breakpoint at the main function. The debugger fails to step into the non-secure code, resulting in an error…

ARM Cortex-R4x SPI Peripheral Integration and Documentation Gaps The ARM Cortex-R4x series, particularly when integrated into System-on-Chip (SoC) designs like the Texas Instruments IWR1642, often presents challenges related to peripheral support and documentation clarity. One such issue is the integration and configuration of Serial Peripheral Interface (SPI) peripherals. While the IWR1642 datasheet mentions the presence…

ARM Cortex-M Interrupt Flag Clearing Issues Across Clock Domains In embedded systems utilizing ARM Cortex-M processors, one of the most subtle yet critical issues arises when dealing with interrupt flag clearing across different clock domains. This problem is particularly pronounced when the core and peripheral operate at significantly different clock speeds, such as a core…

ARM Cortex-M BASEPRI and BASEPRI_MAX Register Access Ordering The ARM Cortex-M architecture provides a robust mechanism for managing interrupt priorities through the BASEPRI and BASEPRI_MAX registers. These registers are critical for controlling the execution priority of the processor, ensuring that high-priority interrupts are serviced promptly while lower-priority tasks are temporarily suspended. However, the interaction between…

Understanding IDAU Security Attribution in ARMv8-M Architecture The ARMv8-M architecture introduces a robust security model that leverages the Implementation Defined Attribution Unit (IDAU) to define the security attributes of memory regions. The IDAU provides critical information about whether a given address is Secure, Non-Secure, or Non-Secure Callable, as well as additional details such as region…

SAMD21 ADC Sampling Characteristics and Power Consumption Challenges The SAMD21 microcontroller, based on the ARM Cortex-M0 core, integrates a high-resolution Analog-to-Digital Converter (ADC) that is critical for precision voltage monitoring in low-power applications. The ADC’s performance is influenced by several key parameters, including the sampling capacitor value, sampling aperture duration, and power consumption during sampling….

ARM Cortex-M TrustZone: Secure Function Execution from Non-Secure SVC Handler The ARM Cortex-M architecture, particularly when implementing TrustZone security extensions, introduces a robust mechanism for isolating secure and non-secure states. This isolation ensures that secure functions, such as secure storage services, are protected from unauthorized access. However, the interaction between non-secure and secure states, especially…

ARM64 Intrinsics and NEON: Understanding the Vector Dot Product Porting Challenge Porting x86_64 intrinsics to ARM64, particularly for operations like vector dot products, involves a deep understanding of both architectures’ SIMD (Single Instruction, Multiple Data) capabilities. The x86_64 architecture relies heavily on SSE (Streaming SIMD Extensions) for vectorized operations, while ARM64 leverages NEON technology for…