Download POS-PHY Level 4 MegaCore Function User Guide

5–12
Chapter 5: Functional Description—Transmitter
Error Flagging and Handling
A DIP-2 error occurs when the DIP-2 code locally calculated on the received status
message does not match the DIP-2 received in the status message. If a DIP-2 error
occurs, the err_ts_dip2 signal is asserted at the end of the calendar sequence for a
single clock cycle.
A framing status error occurs for three regions:
■
When something other than framing is received when the framing pattern is
expected.
■
When an unexpected reserved (‘b11) is received.
■
When Hitless B/W reprovisioning is turned on, and a calendar select word is not
‘b01 or ‘b10.
If a framing status error occurs, the err_ts_frm signal is asserted for one cycle.
The stat_ts_sync signal indicates that the status channel is synchronized. It is
deasserted under the following conditions:
■
At start up, reset, or user rsfrm
■
Continuous framing is received
■
The MAximum Calendar Length or Calendar Multiplier parameters of the status
channel are improperly configured
■
Continuous DIP-2 errors are received (more than DIP-2 bad threshold)
Two 4-bit inputs, ctl_ts_sync_good_theshold and ctl_ts_sync_bad_theshold
control the stat_ts_sync signal.
The stat_ts_sync signal is asserted when a programmed good_level number of
consecutive, non-errored calendar sequences is received. When stat_ts_sync is
asserted, the MegaCore function sends status normally, based on the received status.
The transmitter’s credit and scheduling logic can send normal traffic (refer to
Figure 5–6).
POS-PHY Level 4 MegaCore Function User Guide
May 2013 Altera Corporation