In case anyone is interested, I posted a walkthrough of setting up an Arty A7-100T with the VGA Pmod, controlled by MicroBlaze. Suggestions to improve the write-up are welcome. Thanks!
https://www.rehsdonline.com/post/arty-vga-walkthrough
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The issue is solved!
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It was a specific problem with the monitor and the pattern I was using: If one looks close to the pattern one can see the effect that the colour already slightly changes over the vertical coordinate! Reason: The Monitor scans the VGA signal in order to get the limits for VMAX and blank and with my pattern this worked only partly. I did not correctly blank the VGA channels in the HSYNCH and VSYNCH periods. Regarding the code above, the "active" signal has to be taken into account. Then it works fine.
And yes: No power supply is required for this design. It works without.
mwagner reacted to rehsd in Arty VGA MicroBlaze walkthrough posted
