Architectures and Processors

USB 3.X Implementation Challenges in ARM-Based Microcontrollers The integration of USB 3.X interfaces into ARM-based microcontrollers presents a unique set of challenges that have contributed to its limited adoption. USB 3.X, which includes USB 3.1 Gen 2 (USB3.2 Gen 2 x1) and USB 3.2 Gen 2 x 2, offers significant improvements in data transfer rates…

ARMv8 A57 L1-L2 Cache Bandwidth Measurement Requirements The ARM Cortex-A57 is a high-performance CPU core designed for ARMv8-based systems, commonly used in mobile, automotive, and embedded applications. One critical aspect of optimizing system performance is understanding the bandwidth between the L1 and L2 caches. The L1 cache, typically split into instruction (L1I) and data (L1D)…

AXI Read Response Mechanism and Its Necessity in Data Transfers The AXI (Advanced eXtensible Interface) protocol is a widely adopted on-chip communication standard for high-performance SoC designs. One of its key features is the separation of channels for address, data, and control signals, enabling efficient pipelining and concurrent operations. A critical aspect of the AXI…

AHB-SPMI Signal Deadlock During Linting Signal deadlock violations in RTL linting, particularly in the context of an AHB-SPMI (Advanced High-performance Bus – System Power Management Interface) design, are critical issues that can lead to functional failures in the SoC. A deadlock occurs when two or more signals or processes are waiting for each other to…

ARM Development Studio IDE CPU Selection Error During Compilation The error message "C9912E: No –cpu selected" in the ARM Development Studio IDE typically arises during the compilation process when the ARMCC compiler fails to recognize the target CPU architecture. This issue is particularly prevalent when working with ARM Cortex-A5-based SoCs, such as the Cyclone V…

AXI4 Ordered Write Observation and PCIe Producer/Consumer Ordering Model The AXI4 protocol’s "Ordered Write Observation" property is a critical feature that ensures compliance between the AXI and PCIe ordering models, particularly when integrating PCIe devices into an AXI-based system. This property is essential for maintaining the correct sequence of write transactions, especially in systems where…

CHI Receiver Flit Acceptance During LINKACTIVEREQ Deassertion The CHI (Coherent Hub Interface) protocol, as defined in the ARM AMBA specifications, governs the communication between coherent agents in a system. One critical aspect of CHI is the state transition from RUN to DEACTIVATE, particularly when the transmitter deasserts LINKACTIVEREQ. During this transition, the receiver is required…

Cortex-R52 Integer Division Instruction Support and GCC Compiler Flag Misconfiguration The Cortex-R52 processor, a member of ARM’s Cortex-R series, is designed for real-time applications requiring high reliability and performance. One of its features is support for integer division instructions, specifically the UDIV (Unsigned Divide) and SDIV (Signed Divide) instructions. These instructions are part of the…

AHB Master Behavior During Split and Retry Responses When designing a testbench for an AHB (Advanced High-performance Bus) protocol, understanding the behavior of the AHB master during Split and Retry responses is critical. The AHB protocol defines these responses to manage bus contention and improve system efficiency. A Split response indicates that the slave is…

Cycle-Accurate Cortex-M3 Simulation Using Obfuscated RTL The development of a cycle-accurate Cortex-M3 simulator using obfuscated RTL (Register Transfer Level) presents a unique set of challenges and opportunities. The Cortex-M3, a popular ARM processor core, is widely used in embedded systems due to its balance of performance, power efficiency, and cost-effectiveness. However, creating a cycle-accurate simulation…