Thanks for the info.

I have only tested a solution with each LED controlled in 25% steps of a 1000-step master intensity, clipping at a minimum intensity of 0.002 and it seemed to work quite ok.

Maybe a bit strange to have 2.32 bits/pixel but it was an experiment and I just did a quick-n-dirty and built and emitted 300 fps to a 240*32 monochrome display, so the total result was 60 fps with individual LED intensities. The above should have managed at least twice as many intensities if I had had a bitmap with intensity information, instead of having to switch to 600 fps frame-buffer generation.

If I ever get my hands on a two-LED, or three-LED panel, I'll have to test where the limit is for a more optimized solution. It might be possible to squeeze in tripple-LED support with 8 steps * master intensity, but the hardest part may be to get CPU cycles for new frame buffers.

By the way, it was an ARM chip I abused for this. My '51 work is limited to maintenance of existing products.