Architectures and Processors

APB Protocol Setup and Access Phases: Purpose and Timing The Advanced Peripheral Bus (APB) protocol, part of the ARM AMBA (Advanced Microcontroller Bus Architecture) family, is designed for low-power, low-complexity peripheral interfacing. The protocol operates in two distinct phases: the Setup Phase and the Access Phase. These phases are critical for ensuring reliable communication between…

AMBA 5 CHI Write Merging in Device Memory Type The AMBA 5 CHI (Coherent Hub Interface) protocol specifies that writes must not be merged in the device memory type. This requirement is critical for ensuring correct behavior in systems where memory-mapped devices are involved. Write merging refers to the process by which multiple individual write…

ARM Cortex-M3 DesignStart as a Starting Point for Cortex-M7 Design The ARM Cortex-M3 DesignStart program provides a foundational platform for developers to explore and implement ARM-based SoC designs. It includes the RTL (Register Transfer Level) code for the Cortex-M3 processor, along with a testbench and documentation, enabling users to simulate, synthesize, and implement the design….

TrustZone TZC-400 ACE-Lite Interface Limitations with CHI-Based CMN The TrustZone TZC-400 is a critical component for implementing ARM’s TrustZone security architecture in System-on-Chip (SoC) designs. It acts as a firewall, controlling access to memory regions based on the security state of the system. However, the TZC-400 is designed with an ACE-Lite interface, which is a…

AXI Burst Type Handling: Master and Slave Responsibilities In the context of AXI (Advanced eXtensible Interface) protocol, burst types such as FIXED, INCR, and WRAP are critical for defining how data transfers occur between a master and a slave. The master initiates the transaction by specifying the burst type, and the slave must correctly interpret…

TRACE Signal Functionality in AXI5, ACE5, and ACE5-Lite Channels The TRACE signal in AXI5, ACE5, and ACE5-Lite protocols plays a critical role in system-level debugging and performance monitoring. It is primarily used to provide visibility into transaction paths and data origins, particularly in systems with multiple masters, slaves, and cache-coherent interconnects like the CCI-550. The…

ARM Cortex-M4 Pipeline Efficiency Degradation Due to Frequent Interrupts The ARM Cortex-M4 processor, like many modern embedded processors, employs a pipelined architecture to enhance instruction throughput and overall performance. The pipeline is divided into several stages, each handling a specific part of the instruction execution process, such as fetch, decode, execute, memory access, and write-back….

ARM Exclusive Access Sequence Disruption by Intermediate Normal Store In ARM-based systems, exclusive access sequences are critical for implementing atomic operations, such as semaphores and spinlocks. These sequences typically consist of a Load-Exclusive (LDX) instruction followed by a Store-Exclusive (STX) instruction. The LDX instruction marks a memory location for exclusive access, and the STX instruction…

ARM Cortex Series and AMBA Bus Architecture Overview Requirements The need for a comprehensive textbook or resource that covers the ARM Cortex series (M, R, A) and AMBA bus architectures (AHB, AXI, APB) is critical for SoC designers and verification engineers. Such a resource should provide a detailed overview of the ARM architecture, including block…

Understanding the Iris Debug Interface and Its Support Library The Iris debug interface is a powerful tool for debugging ARM-based System-on-Chip (SoC) designs, offering a robust framework for connecting debuggers, clients, and plugins to simulation models or real hardware. The Iris Support Library (libIrisSupport.a or libIrisSupport.lib) is a critical component that facilitates this interaction. It…