Avalon® Interface Specifications

ID 683091
Date 1/24/2022
Public

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5.11. Signal Details

  • startofpacket—All interfaces supporting packet transfers require the startofpacket signal. startofpacket marks the active cycle containing the start of the packet. This signal is only interpreted when valid is asserted.
  • endofpacket—All interfaces supporting packet transfers require the endofpacket signal. endofpacket marks the active cycle containing the end of the packet. This signal is only interpreted when valid is asserted. startofpacket and endofpacket can be asserted in the same cycle. No idle cycles are required between packets. The startofpacket signal can follow immediately after the previous endofpacket signal.
  • empty—The optional empty signal indicates the number of symbols that are empty during the endofpacket cycle. The sink only checks the value of the empty during active cycles that have endofpacket asserted. The empty symbols are always the last symbols in data, those carried by the low-order bits when firstSymbolInHighOrderBits = true. The empty signal is required on all packet interfaces whose data signal carries more than one symbol of data and have a variable length packet format. The size of the empty signal in bits is ceil[log2(<symbols per cycle>)].