A11.1 About the ACP

The optional Accelerator Coherency Port (ACP) is implemented as an AXI4 slave interface with some restrictions.

  • 128-bit read and write interfaces.
  • ARCACHE and AWCACHE are restricted to Normal, Write-Back, Read-Write-Allocate, Read-Allocate, Write-Allocate, and No-Allocate memory. ARCACHE and AWCACHE are limited to the values 0b0111, 0b1011, and 0b1111. Other values cause a SLVERR response on RRESP or BRESP.
  • Exclusive accesses are not supported.
  • Barriers are not supported. The BRESP handshake for a write transaction indicates global observability for that write.
  • ARSIZE and AWSIZE signals are not present and assume a value of 0b100, 16 bytes.
  • ARBURST and AWBURST signals are not present and assume a value of INCR.
  • ARLOCK and AWLOCK signals are not present.
  • ARQOS and AWQOS signals are not present.
  • ARLEN and AWLEN are limited to values 0 and 3.
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