Versal ACAP Technical Reference Manual (AM011)

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1.4 English

The interconnect includes the AXI and APB interface protocols. The AXI data width can be 32, 64, or 128 bits. The APB protocol is used for the 32-bit programming interfaces and low-bandwidth data ports.

The smallest data transaction is a single 32-bit word. The largest transaction is a 128-bit data word with a burst of 256 data cycles (4 KB burst size).

  • AXI: Sources can burst up to 256 words
  • APB: Receive single 32-bit data word
  • NPI: Receive burst of 32-bit data words
  • AXI: Destinations can only receive up to 16 words

Transaction Adaptation

The interconnect manages transaction requests. When the source and destination have a different data width or burst length, the transaction is modified, including breaking up a long burst into shorter bursts.

When an AXI transaction includes a 256-word burst, but the destination only supports 16-word bursts, the interconnect breaks the transaction into 16-word bursts with the proper data width for the destination interface.