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AR# 29238

Virtex-4 Video Starter Kit (VSK) - Compiling the VIODC system generator design fails in MAP


Keywords: Video Starter Kit, VSK, VIODC, 9.1, 9.2, ERROR:Pack:946, XIL_MAP_FIXIOSTD

When following the steps described in the Video Starter Kit User Guide in chapter 7, which describes how to generate a ".bit" file of the VIODC System Generator using ISE 9.x, I find that the generation fails in MAP with the following error:

ERROR:Pack:946 - The I/O component "vio_up_clk_lvds_P" has an illegal IOSTANDARD value. Components of type DIFFM do not support IOSTANDARD LVCMOS25. Please correct the IOSTANDARD property value.

This does not happen in the previous version of ISE. Why does this happen, and how do I work around this issue?


This happens because the order in which the IOSTANDARDS are defined in the provided "viodc_sgl_12.ucf" file is wrong. It did not happen in previous versions of ISE before 9.x because the MAP rules changed in ISE 9.x. More information on this can be found in (Xilinx Answer 24292).

To work around this problem, move the following lines in the "viodc_sgl_12.ucf" file as described below:

# Start of lines to move
#IO Standards
NET "vio_up_clk_lvds_P" IOSTANDARD = "LVDS_25_DT";
NET "vio_up_clk_lvds_N" IOSTANDARD = "LVDS_25_DT";
# End of lines to move

Move these two constraints to any place below the following lines in the constraints file:

# Place the above code underneath this section
# constrain vio_up signals coming from the XGI connector
NET "vio_up*" IOSTANDARD = "LVCMOS25";
OFFSET = IN 2.8 ns BEFORE "vio_up_clk_lvds_P";
#- End of section

This will assign the correct IOSTANDARD to the "vio_up_clk_lvds_P" & "vio_up_clk_lvds_N" signals.

The "viodc_sgl_12.ucf" will be fixed in a future release of the VIODC design.

AR# 29238
Date 08/26/2009
Status Archive
Type General Article