The MAC receiver can capture all valid frames regardless of the address using the copy all frames feature The promiscuous mode is enabled when network_config [copy_all_frames] is set = 1. In this mode, all RX frames are copied into the RXFIFO except for the frames that are:
- Too long (over 1536 bytes)
- Too short (under 64 byes), or
- GMII's RX error (rx_er) signal assert during reception
If the RX frame includes an FCS error, the frame is only captured if the network_config [ignore_rx_fcs, 26] bit is set = 1.