NIC400 AXI4 Bridge Configuration and Outstanding Transaction Limitation The NIC400 interconnect is a highly configurable and scalable interconnect IP from ARM, designed to support AMBA AXI, AHB, and APB protocols. It is widely used in ARM-based SoC designs to manage communication between multiple masters and slaves. One of the key features of the NIC400 is…
Cache State Behavior in ACE Protocol for ReadShared and ReadOnce Transactions The ARM ACE (AXI Coherency Extensions) protocol defines a set of rules and mechanisms to ensure cache coherency in multi-core systems. Two critical transaction types in ACE are ReadShared and ReadOnce, which have distinct implications for cache state updates. Understanding how these transactions interact…
AXI Downsizer Address and Data Handling in 64-bit to 32-bit Conversion The BP131 AXI Downsizer is a critical component in ARM-based SoC designs, particularly when interfacing between AXI masters and slaves with differing data widths. One of the most common use cases involves converting a 64-bit AXI transaction into one or more 32-bit transactions. This…
QACTIVE Assertion and QDENY Dependency in AMBA Q-Channel The AMBA Low Power Interface (Q-Channel) is a critical component in ARM-based SoC designs, enabling efficient power management by facilitating communication between power controllers and peripheral devices. The Q-Channel consists of several signals, including QACTIVE, QDENY, and PWAKEUP, which play pivotal roles in managing power states. A…
Cache Line Faults and Their Impact on ARM-Based SoC Performance Cache line faults, often referred to as "bad bits," can significantly degrade the performance and reliability of ARM-based System-on-Chip (SoC) designs. These faults can manifest as calculation errors, process failures, or even system crashes, particularly in scenarios where data integrity is critical. The cache memory,…
ARM Cortex-R5 Heroncell_DCCM Module fault_s Signal Unknown at Power-Up The fault_s signal in the Heroncell_DCCM module of the ARM Cortex-R5 is holding an unknown value (X) during the power-up sequence. This issue arises during the SOC_FSM_WAIT_POR_STABLE state, where the fault_s signal is asserted with the clock running. The unknown value propagates to the dccmout and…
ARM Artisan GPIO PO and POE Signal Functionality The ARM Artisan GPIO library provides two critical signals for pad control and data integrity: PO (Parametric Output) and POE (Parametric Output Enable). These signals are essential for managing the interface between the pad and the core logic, ensuring that data is correctly transmitted and received while…
ARM Cortex-M3, R5, and A-Series Debug Integration Challenges When designing a heterogeneous ARM-based SoC with multiple cores such as Cortex-M3, Cortex-R5, and Cortex-A series processors, one of the critical decisions revolves around the debug infrastructure. The debug infrastructure is essential for ensuring visibility into the system during development, testing, and post-silicon validation. The primary challenge…
AXI QoS Mechanism and Observed In-Order Behavior The AXI (Advanced eXtensible Interface) protocol incorporates Quality of Service (QoS) signaling to manage transaction priorities and optimize system performance. The QoS values, represented by the AxQoS signals (awqos for write transactions and arqos for read transactions), are intended to influence the priority and ordering of transactions within…
HTRANS Busy State and HREADY Signal Interaction During AHB Read Operations The interaction between the HTRANS signal and the HREADY signal in the ARM AHB (Advanced High-performance Bus) protocol is a critical aspect of ensuring correct data transfer between the master and slave devices. The HTRANS signal indicates the type of transfer being initiated by…