Turbo Intel® FPGA IP User Guide

ID 683734
Date 9/30/2021

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4.3.1. Packet Format Errors

The Turbo IP interface complies with Avalon Streaming protocol. The Turbo IP is able to detect the following malformed Avalon Streaming sink packets that are mistakenly fed to the IP. If the IP detects an error , the current packet gets dropped and the output port source_error outputs the corresponding error code a few cycles later. Then, the IP continues to process the next available packet. Please note that the IP may not be able to detect complex error cases correctly. For instance, two or more of the following cases occur at the same time in a packet. Therefore, it is always recommended to protect the IP against malformed input packets when use in production.
  1. Error code "01" indicates missing sink_sop.
  2. Error code "10" indicates missing sink_eop.
  3. Error code "11" indicates unexpected sink_sop or sink_eop.
  4. Default "00" indicates no errors.
The IP input port sink_error accepts error code provided from the upstream block. However, a non-zero value from sink_error does not result in the current packet being dropped by the IP immediately. Instead the IP always detects errors itself. If IP founds an error, the current packet processed as normal and source_error is "00". If IP founds an error, the source_error signal is a combination of sink_error and the error detected by the IP itself, as follows:
  1. If error_found= 00, sink_error= any, then the source_error= 00.
  2. If error_found= 01, sink_error= 00 or 01, then the source_error= 01
  3. If error_found= 01, sink_error= 10 or 11, then the source_error= 11.
  4. If error_found= 10, sink_error= 00 or 10, then the source_error= 10.
  5. If error_found= 10, sink_error= 10 or 11, then the source_error= 11.
  6. If error_found= 11, sink_error= any, then the source_error= 11.