Apologies for the blurry focus. It's really hard to get a sharp picture just holding my camera. This should, however, show my progress. I can produce color text now, though there are still some noise issues to iron out. I'm using a new timing board design that's a lot simpler and I haven't yet looked at eliminating noise from it. I only just got it working.
The long-thin board that's closer to the camera is the timing stage that produces black-and-white output. The smaller board behind it is the color stage. Both of these boards are only testbed designs that allow me to fine-tune things, experiment with noise reduction, palettes, etc. A "production" version would also require a proper frame buffer, character ROM and RAM, and an input stage that interfaced with the Inty's bus. One step at a time, though.
The color stage incorporates a small 2k RAM chip that I use for storing the color palette. On startup, the Arduino programs it with the four timeslice values that need to be output for a given color, similar to how the inty's color chip works. With this new timing board, the palette isn't matching the Inty palette so another bit of experimenting will have to involve messing around with timeslice values. I might save that for a different color stage, though: I'm working on a design for the color stage that supports 8 bits of resolution for timeslice values instead of only 4.
As in earlier pics, the left half of the text looks noisy on my Dell monitor. That's because it doesn't like the noninterlaced format that the Inty outputs, and so it's getting confused. The right half is what it would normally look like on a TV.
Edited by JohnPCAE, Sat Mar 10, 2018 4:39 AM.