A lot of us have a soft spot for retrocomputers, and there’s nothing quite like running original hardware. Unfortunately if you’re after the truly original touch then that means carrying along the family TV from 1982, and that’s where life becomes annoying. What if there were a way you could easily drive an LCD panel from a classic video controller? Help is at hand for owners of TI TMS9928A video chips, courtesy of [umaker], with a clever interface board that drives an SPI or parallel TFT.
At its heart is not the FPGA you might expect, but an STM32G4 microcontroller on an STM Nucleo board. This digitizes the R-Y and Y components from the TMS chip which would originally have been destined for an NSC or PAL encoder, does the color conversion through its algorithm, and transfers the result to the screen. This is a task which would back in the day when NTSC or PAL were king have been seen as extremely computationally intensive, so it’s a mark of just how capable an STM can be that a few dollar microcontroller can do it.
We can see this technique proving to be extremely useful across a lot of different retro color graphic applications. We’re not sure whether its lag would be too much for a light gun game, but it would be nice to think that it would result in handheld retro machines.
We encountered this project previously, when as part of its development he needed a sync separator.