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Virtex Configuration: Using LOUT writes for debugging purposes in Serial Modes
Record #8110
Problem Title:
Virtex Configuration: Using LOUT writes for debugging purposes in Serial Modes
Problem Description:
Urgency: Standard
General Description: I need to debug my bitstream. What can I do to tell what is going on?
Solution 1:
The LOUT configuration register is a pipeline register to the DOUT pin. By embedding LOUT
writes in the bitstream, it will indicate that the downloading reached a certain point. Also, it
will necessarily mean that the device is synchronized.
The best way to embed an LOUT write is to use a hex edition and place it into the .bit file. However,
it must be inserted between two packets. Refer to (Xilinx XAPP138) for a description on packets and the
bitstream format. The packet header for an LOUT write of 1 32-bit word is 0x30010001. This must be
followed by a single DWord of data. This data can be anything, which is usefull for debugging
purposes. LOUT writes can be embedded anywhere in the bitstream, and can be invaluable for
verification of successful downloads.
End of Record #8110 - Last Modified: 02/03/00 08:16 |
