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  3. AR# 40355: Aurora 8b/10b - FRAME_ERR stays high after reconnecting cable

AR# 40355

Aurora 8b/10b - FRAME_ERR stays high after reconnecting cable

Description

When a link is interrupted, for instance by unplugging the link cable, it can happen that at reconnection the FRAME_ERR signal is permanently asserted by the core. In this situation it can only be deasserted by resetting the core. This behavior only happens in 4-byte mode.

Solution

This issue can be fixed be replacing the following code in the sideband_output file:

always @(posedge USER_CLK)
FRAME_ERR_RESULT <= `DLY FRAME_ERR || (END_AFTER_START && !START_WITH_DATA) ||
(END_BEFORE_START && START_WITH_DATA && !storage_not_empty_c) ||
(END_BEFORE_START && !START_WITH_DATA && total_lanes_c == 0);

with:


always @(posedge USER_CLK)

FRAME_ERR_RESULT <= `DLY (END_AFTER_START && !START_WITH_DATA) ||
(END_BEFORE_START && START_WITH_DATA && !storage_not_empty_c) ||
(END_BEFORE_START && !START_WITH_DATA && total_lanes_c == 0);

This is expected to be fixed in ISE 13.3 software.
AR# 40355
Date 12/15/2012
Status Active
Type General Article
IP