Error Frame

An Error Frame occurs when the PHY asserts the error signal during reception, which are gm_rx_err (GMII or SGMII), rmii_rx_err (RMII), mii_rx_err (MII) , or RGMII decoded error.

Preamble or SFD Exception—If an error signal is asserted during a preamble or a start frame delimiter (SFD), the sequence is silently discarded. No statistic counters are incremented.

Frame Termination—If an error signal is asserted after an SFD is detected:
  1. The Triple Speed Ethernet MAC core immediately terminates the frame.
  2. The frame received up to the point of termination is validated according to the precedence rules in Table 1.
  3. The last 4 octets of a data received before termination are interpreted as a frame check sequence (FCS). As these octets do not represent the valid checksum for the truncated frame, the FCS validation fails. If the frame length during termination is valid (neither undersized nor oversized), this resulting FCS failure will increment the aRxFrameCheckSequenceErrors counter.