Configuring and connecting the Cortex-A53 processors

This system is based around two Cortex-A53 clusters, which provide high performance coupled with low-power usage.

Configuration

In this SoC, the following configuration options were chosen for the Cortex-A53 clusters:

  • Both clusters have the maximum of four cores. You can choose between one and four cores for each Cortex-A53 cluster.
  • Each cluster has an AXI Coherency Extensions (ACE) interface that connects to a CCI-500. You can choose to have either a Coherent Hub Interface (CHI) or an ACE interface for each Cortex-A53 cluster.
  • Each cluster is configured to integrate with either an external GICv3 or an external GICv4 distributor, in this case the GIC-500. You must enable the external Generic Interrupt Controller (GIC) interface for this option. The option to integrate with an external GICv2 distributor component is possible. If you use this option, the internal GIC must be disabled.
  • Each cluster supports a Floating Point Unit (FPU) and Neon. We recommend including this functionality for a system on which you intend to run Linux.
  • Each core has a L1 cache of 32KB. You can configure the L1 caches for a core to be between 8KB and 64KB.
  • The Cortex-A53 clusters share an L2 cache of 1024KB. You can configure the L2 cache for a cluster to be between 128KB and 2048KB.
  • All L1 and L2 caches have Error Correcting Code (ECC) included. This feature provides fault protection capability for the caches.
Connections

Each Cortex-A53 cluster includes the interfaces that are shown in the following table:

 Interfaces Description 
 ACE master Each cluster has an ACE master interface that connects to the CCI-500. This interface allows the cores within the cluster to access memory, peripherals, and other components.
 Stream protocol Each cluster has a stream protocol interface that can connect to an external interrupt controller. In this case, the external interrupt controller is a GIC-500.
 Debug APB3 slave  Each cluster has an APB3 debug slave interface. This interface enables a debug control subsystem, in this case a CoreSight SoC-400 subsystem, to access system resources. For example, the subsystem can use this interface to set watchpoints and breakpoints.
 ATB master Each core has an AMBA Trace Bus (ATB) master interface. These interfaces transmit trace data from the Embedded Trace Macrocell (ETM) of each core. ETMs capture the execution of a program running on a core and this information is known as trace data. In this SoC, the trace data is sent to a CoreSight SoC-400 subsystem. Components in the subsystem store trace data on-chip and off-chip. External analyzers can decompress the data as required.
ACP Each cluster has an Accelerator Coherency Port (ACP). This interface provides access for non-cached masters, such as a DMA controller. This interface only supports a subset of AXI transaction types and is not used in this SoC.
MBIST
Each cluster has a Memory Built-in Self-test (MBIST). This interface supports performing a manufacturing test of the memories that are embedded in the Cortex-A53 process.
DFT
Each cluster has a Design For Test (DFT) interface. This interface enables an industry standard Automatic Pattern Generation (ATPG) tool to test logic outside of the embedded memories.
Cross-trigger
Each cluster has a cross-trigger interface. This interface allows you to connect, through a Cross Trigger Matrix, to the cross-trigger channel interfaces of other clusters, and Cross Trigger Interface components in the system. A Cross Trigger Matrix provides:
  • The connectivity that supports cross-cluster halting.
  • The connectivity to communicate a trace collection trigger signal for a trace subsystem.
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