SX52(48) VGA Update with pics!

cbmeeks · 2006-09-15 02:44

I got some nice pictures of my VGA circuit. I've got some weird timing issues. The image looks SOLID with an 80 Mhz OSC but if you look really close, you can see that each scanline "zig-zags". So I am sure I have something off by one.

Another weird thing is that this is 157 pixels!! not 160. 160 caused the screen to really screw up??? I know why. Timing. When I ran sxsim against it (at 160 pixels) I was taking 65 clocks too much per scanline. That is way off. Reducing the pixels down to 157 gets me within ONE clock of perfect. Not too bad.

This weekend I am going to narrow that down and get it perfect. I actually have about 7 clocks free per pixel at 157. So I should be able to get 256 pixels across and still have a clock or two for updating the SRAM's address bus.

Comments welcomed.