I saw this VGA demo for a 640x480 monitor
and I would like to run it on my monitor using a Basys-3 FPGA. The GPIO demo code for the Basys-3 board works on my monitor, so I know it is possible to display it given 1280x1024 resolution, so I decided to modify their code accordingly. The full code is in a zip file which can be downloaded from that link (NERP_demo.zip).
I used values I found from this link and so the part of their code I modified from the vga640x480.v file looks like this:
// video structure constants parameter hpixels = 1280;// horizontal pixels per line parameter vlines = 768; // vertical lines per frame parameter hpulse = 128; // hsync pulse length parameter vpulse = 7; // vsync pulse length parameter hbp = 216; // end of horizontal back porch parameter hfp = 88; // beginning of horizontal front porch parameter vbp = 29; // end of vertical back porch parameter vfp = 3; // beginning of vertical front porch // active horizontal video is therefore: 784 - 144 = 640 // active vertical video is therefore: 511 - 31 = 480
However, I still can't get their demo to run on my monitor. Before I changed their values, when I tried running the code, my monitor was telling me to switch to 1440x900. After I changed the values, I don't get that suggestion anymore, but the screen is still black. I don't know what to do.