Endpoint Block Plus v1.9 - Transmit side stalls when sending packets, causing trn_tdst_rdy_n to deassert indefinitely
Description
Keywords: transmitter lock up, stall, trn_tdst_rdy_n
Known Issue: v1.9.2, v1.9.1, v1.9, v1.8, v1.7.1, v1.7, v1.6.1, v1.6
A problem can occur where the transmit side seems to lock up or stall indefinitely. The user will recognize this happening when trn_tdst_rdy_n deasserts forever.
Solution
There was a problem in the logic that tracks data credits used to work around the known restriction titled "TX Transmission Issues Due to Lack of Data Credits," which is listed in the known restrictions section of the integrated block's user guide located at:http://www.xilinx.com/support/documentation/user_guides/ug197.pdf
The logic is too conservative when counting and estimating data credits, which eventually leads to the lock up condition.
A fix for this is available in the v1.9 Rev 3 patch. See (Xilinx Answer 31572) for access to the patch.
Revision History
02/25/2009 - Initial release