Author: System on Chips

ARM Cortex-A53 L2 Cache Organization and L2MERRSR_EL1 Error Parsing The ARM Cortex-A53 processor features a shared L2 cache that plays a critical role in system performance and reliability. The L2 Memory Error Syndrome Register (L2MERRSR_EL1) is a key diagnostic tool for identifying and analyzing cache-related faults. In the context of a Zynq UltraScale+ (ZU+) system,…

ARM TrustZone TZC-400 Access Control Limitations and System Topology The ARM TrustZone TZC-400 (TrustZone Address Space Controller) is a critical component in systems requiring secure memory and peripheral access control. It is primarily designed to enforce memory access policies by filtering transactions based on their security attributes, such as Non-Secure (NS) or Secure (S) states,…

NVIC_ICPR and NVIC_IABR Register Behavior During PRIMASK Manipulation The behavior of the NVIC_ICPR (Interrupt Clear Pending Register) and NVIC_IABR (Interrupt Active Bit Register) during the manipulation of the PRIMASK register in ARM Cortex-M processors is a nuanced topic that requires a deep understanding of the ARM architecture’s interrupt handling mechanisms. When the PRIMASK register is…

Exception Handling and Stack Pointer Transition in Cortex-M3 The Cortex-M3 processor, as part of the ARMv7-M architecture, employs a sophisticated exception handling mechanism that relies on two stack pointers: the Main Stack Pointer (MSP) and the Process Stack Pointer (PSP). The MSP is typically used in Handler Mode (privileged mode during exception handling), while the…

ARM Cortex-M7 Exception Handling and R7 Register Corruption During EXC_RETURN The ARM Cortex-M7 processor, known for its high performance and advanced features, is widely used in embedded systems. However, a critical issue has been observed where the R7 register is not preserved during exception return, specifically when executing the EXC_RETURN sequence. This issue manifests in…

ARM Cortex-M4 Cache Coherency Problems During DMA Transfers When working with ARM architectures, particularly in multi-core or multi-processing environments, understanding the relationship between shareability domains, cache maintenance, and memory barriers is critical. The ARM architecture provides mechanisms to ensure that memory operations are properly synchronized across different processing elements (PEs) within the same or different…

Cacheable Memory Regions in ARM Cortex-M7 with MPU Disabled When the Memory Protection Unit (MPU) is disabled in an ARM Cortex-M7 processor, the memory attributes for different regions are determined by the default system address map. The Cortex-M7 core relies on this default address map to define the cacheability and memory attributes of various address…

Understanding SMMU and Huge Pages in ARM Architectures The System Memory Management Unit (SMMU) in ARM architectures plays a crucial role in managing memory access for devices that are not directly connected to the CPU. The SMMU translates virtual addresses to physical addresses, similar to how the CPU’s Memory Management Unit (MMU) operates. One of…

ARM Cortex-A Series PMU Events for Remote Memory Access and Snooping The ARM Cortex-A series processors, particularly those based on the ARMv8-A architecture, incorporate Performance Monitoring Units (PMUs) that provide detailed insights into system behavior, including memory access patterns and cache coherency operations. One critical aspect of performance analysis in multi-core and multi-cluster systems is…

GPIO Access Issues on ARM Cortex-A55 in Secure EL3 State The core issue revolves around the inability to read or manipulate GPIO pins on the ARM Cortex-A55 core of the NXP i.MX93 processor while operating in the secure state at Exception Level 3 (EL3). The user is attempting to perform bare-metal development tasks, such as…