Using a NIC-400 in the SoC

The CCI-500 does not provide all the interfaces that this SoC requires. The SoC needs more AXI interfaces and APB interfaces, which the CCI-500 does not support.

The solution requires a second interface that supports APB interfaces and a larger number of AXI slave and master interfaces. The CoreLink network interconnect family offers the NIC-400 and NIC-450 to help with this.    

The CoreLink NIC-400 is:

  • Highly configurable
  • Offers Network on Chip (NoC)-like properties
  • Provides fully configurable, hierarchical, low latency, and low-power connectivity for AXI, AHB-Lite, and APB interfaces
  • Consists of up to 128 masters and 64 slaves of AMBA protocols. AXI and AHB-Lite protocols are supported for the master and slave interfaces. The master interfaces also support APB protocols.
Configuration

To configure an NIC-400, you must use Socrates. Socrates is available as part of the Arm Flexible Access program. The following list broadly covers the steps that you need to follow to configure an NIC-400:

  1. Define the high-level specification, which covers the overall look and behavior of the NIC-400. The high-level specification includes clock domains, slave interfaces, and master interfaces. To define the interfaces, select the protocol and choose appropriate values for data width, ID width, and other parameters.
  2. Create the memory map. This map enables a transaction to be sent to the correct interface. For each address, the NIC-400 can determine which port to use.
  3. Set the paths. These paths determine which interfaces can talk to each other. The paths allow Socrates to optimize the NIC-400. Setting paths also increases the security of the NIC-400 by facilitating physical path removal between non-communicating interfaces.
  4. Generate the microarchitecture. During this process, Socrates checks the configuration is valid and creates internal connections for the NIC-400. The internal blocks are connected using switches. The switches match the paths between the interface that you previously defined in step 3.
  5. Edit the microarchitecture to obtain more performance. When generating microarchitecture, Socrates optimizes the result for area. This step gives you a chance to look at performance. In addition, you can also add buffering, add register slices, and resolve deadlocks.
  6. Perform a full validation to check any changes that you made. Designs are run against the Design Rule Check (DRC). The DRC checks whether an NIC-400 design is valid.
  7. Change the high-level specification as required and feed the result back into the microarchitecture. At this stage, changes like this are still possible and can also be validated. The design is now finalized and ready for the next step.
  8. Generate the RTL. The top-level RTL contains the clock ports, and slave and master interfaces. The NIC-400 is now ready for connection to other IP.

In this SoC, the NIC contains five AXI interfaces and eight APB interfaces.

Connections

The following table shows the IP that NIC-400 interfaces connect to:

Interface Connection 
AXI4 master  Connect to the:
  • GIC-500
  • Mali-G52  
AXI4 slave  Connect to the:
  • GIC-500
  • CCI-500
  • SoC-400 subsystem
APB master   Connect to the:
  • SoC-400 subsystem
  • TZC-400
  • MMU-500
  • Timers
  • GPIO
  • UART
  • Watchdog timer
  • PCK-600 Power Policy Unit

Note: Any extra APB peripherals connect to APB master interfaces.

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