XAUI v12.3 Product Guide
134
PG053 April 6, 2016
Appendix C:
Debugging Designs
Link Bring-Up
The following link initialization stages describe a possible scenario of the Link coming up
between device A and device B.
Stage 1: Device A Powered Up, but Device B Powered Down
• Device A is powered up and reset.
• Device B powered down
• Device A detects a fault because there is no signal received. The Device A XAUI core
indicates an RX local fault.
• The Device A MAC reconciliation layer receives the local fault. This triggers the MAC
reconciliation layer to silently drop any data being transmitted and instead transmit a
remote fault.
• RX Link Status = 0 (link down) in Device A
X-Ref Target - Figure C-3
Stage 2: Device B Powers Up and Resets
• Device B powers up and resets.
• Device B XAUI completes Synchronization and Alignment.
• Device A has not synchronized and aligned yet. It continues to send remote faults.
• Device B XAUI passes received remote fault to MAC.
• Device B MAC reconciliation layer receives the remote fault. It silently drops any data
being transmitted and instead transmits IDLEs.
• Link Status = '0' (link down) in both A and B.
Figure C
‐
3:
Device A Powered Up, but Device B Powered Down
MAC/XAUI
MAC/XAUI
Device A
Device B
Link
Down
TX Idle SRF
Idle SRF RX
RX No Signal
No Signal TX
X13724