DE2 board VGA Dispaly

Hi Monish.

Obviously you did a mistake (if you see it dark), or, you are not catching the correct order pixel image. You'll need your image in 8bit gray scale to do that. We're comming back to the first part of the problem, I ask you, How do you get the correct pixels image in SRAM ??

Let me explain why the shift by 2.

The ADV7123 DAC VGA chip of the DE2 board have three inputs of 10 bit wide each. They are R9-R0, G9-G0, and B9-B0.

IF you have per example (taking R input only in this example), all bits R9-R0 in "0", the R output will be off, but if you have all bits R9-R0 in "1" you'll have the maximun bright in the R channel output. (This is for 1023 dec.)

OK, If your data for R channel is 255 := 8'b11111111 you'll want maximun bright in the R output, but your DAC chip needs this: 10'b1111111111, so to aproximate to this, you'll need to get this: 10'b1111111100, and how to get that ?

This is shifting by 2 your eight bit data.

Do that for all R,G,B channels, and you'll get almost a "white pixel" for your RGB data in "255" each one of them.

Is it clear now ?

Cheers.

Alberto.