Altera POS-PHY Level 4 IP Core - Manual (Page 55)

Chapter 4: Functional Description—Receiver 4–17
Error Flagging and Handling
December 2014 Altera Corporation POS-PHY Level 4 IP Core User Guide
DIP-4 Out of Service Indication
A DIP-4 out-of-service (stat_rd_dip4_oos) status signal provides an in-service or out-
of-service indication based on recent DIP-4 errors. Two 4-bit inputs are associated
with this signal: good_level (ctl_rd_dip4_good_threshold) and bad_level
(ctl_rd_dip4_bad_threshold).
If the receiver is in service (the stat_rd_dip4_oos is low) and one or more DIP-4
errors are detected (up to 8 in 128-bit mode) in the current rdint_clk cycle, the bad
counter is incremented. If the bad counter reaches the bad_level threshold, the
receiver goes out of service by asserting the stat_rd_dip4_oos signal. If any of the
DIP-4s received in the current cycle are good, the bad counter is cleared. So if both
good and bad DIP-4s are received in the current cycle the bad counter is also cleared.
If no control words are received, nothing happens.
If the receiver is in service and the bad threshold is set to 0 or 1, the receiver goes out
of service as soon as a single DIP-4 error is detected.
If the receiver is out of service and there are no DIP-4 errors in the current rdint_clk
clock cycle, the good counter is incremented. If the good counter reaches the
good_level
threshold, the receiver goes in service and asserts. If any DIP-4 errors are
received in the current cycle, the counter is cleared. If no control words are received,
nothing happens.
Figure 4–7. DIP-4 OOS State Machine