Hot-plug logic in Aurora 64B/66B designs is based on the received clock compensation characters. Reception of clock compensation characters at the RX interface of Aurora 64B/66B infers that the communication channel is active and not broken. If clock compensation characters are not received in a predetermined time, the hot-plug logic resets the core and the transceiver. The clock compensation module must be used for Aurora 64B/66B designs.
IMPORTANT: It is highly recommended to keep hot plug logic enabled for predictable operation of the link.
The description of the hot-plug sequence follows.
1. Requirements: Before replacing the card, powering down a specific system, or reprogramming the bit file, it is required to assert reset before performing a hot plug sequence so that the remote agent channel goes down gracefully and gets ready when the link is removed and reconnected.
2. How it works: When reset is asserted for a time equal to 128* user_clk time_period before performing a hot plug sequence, enough NA_IDLES are generated for the remote link to deassert Channel Up without errors.
3. Limitations: If the preceding sequence is not followed, SOFT/DATA errors are possible so that the link does not have a graceful shutdown.