VDP-NTSC

Been busy with work but I figured before I dash off I’d post the VDP-N core. Remind me to add some comments and stuff when I’m back

VDP1-N

P.S. It needs an external 28.636mhz clock and an 8-bit (4-bit will actually do) R2R ladder.

Mario Redux

XMOS mario demo running in NTSC.

The aspect ratio is somewhat off because of the slightly higher frequency and the colors are 3 bits per component instead of 5. All in all though, kinda nifty to be able to generate NTSC video in software

Lights out…

PCB’s arrived!

First peek at my VGA adapter board..

Some serious doubts whether or not it was the right thing to go with SMT, but hey.. at least it’s compact, right? If anyone’s interested, drop me a line… On a sidenote, my NTSC core is close to being done! Only thing remaining is the vertical timing and integrating it with VDP1-N ( for NTSC ).

Now where was I…

Colorbars?!

Colors are still somewhat saturated, but it looks like it’s all in working order! No vertical timing yet which is why my iPhone picked up some of the diagonal interference..

Timing is everything..

Actually, that’s only half the story..

Been a while since I posted so I figured I’d give y’all a bit of an update. While I’m still waiting for my PCB’s and SMT parts I’ve been beavering away on an NTSC composite color core. I’ve got some color-bars showing up but still need to find the proper voltage levels, which seems to throw off some of the colors ( like yellow ). Maybe it’s because I’m using 5% tolerance resistors.. Meh, we’ll see… Ordered some 1% just in case though..

Anyway, if/when I get it to work it should be able to display 512 colors on-screen ( 3:3:3 ) which isn’t all that great, but if it was enough for Sega, it’s enough for me

The nice thing though, is that all the encoding is done in software and saves you a chip! With my new goal being to create an NTSC game console on a single XS1-L, this should bring that one step closer to reality…

w00t!

VDP1 Update

Quick update on VDP1:

- Replaced ‘mkmsk’ with ‘zext’ where possible
- Added VDP_CONTROL register to enable / disabled things
- Added HSRAM support for BG0/1, allowing you to scroll each background on a per line basis.
- Redefined some registers to be more consistent ( SPRITE / TILE )

The updated core is available here:

VDP1

Time permitting, I’ll see if I can knock-up a ‘proper’ sine-wave demo

PCB’s ordered..

Here’s a first look at the ‘VGA’ PCB for XC-2/5 boards. They’re rather tiny, measuring 1.9 inches across and should (famous last words) fit right onto port-1 or 3A/B. Each component has a 5-bit R2R ladder and the adapter can therefore display 32768 colors on-screen simultaneously! 1K/510ohm resistors give a bright enough display without exceeding the current capabilities of the XS1.

Should get everything in the next week or so but realistically probably more something like 10 days. Stay tuned!

VDP1 Preliminary Release

Preliminary release of my Video Display Processor under the MIT license. VGA and NES controller adapter boards should be available later this month!

VDP1

The source will also be posted on xlinkers…