Conversion of the schematics of the Atari STE motherboard into Kicad

[Sporny Kun]

The title says all, I have converted the existing schematics into Kicad. This is the 1.0.0 release, and hopefully there will be no erratum.

https://github.com/sporniket/kicad-conv ... /tag/1.0.0

The release provides a PDF with the schematics, a PDF with the silkscreen of the motherboard reconstruction, and a ready to use Kicad project (libraries included).

For the schematics, I have decided that :

• Symbols for the ICs will show the physical layout of the pins, as it makes it easier to spot the pin on the real IC (for me at least). And because thanks to that, the GSTMCU still fits on an A4 sized sheets. On one occasion I deviated from this choice (for the dma sound amplification and filtering) as it obfuscated too much the circuit.
• Each original sheet is splitted so that each sub-part is printable on a A4 sized sheet.
• A Table of content

 

I also have mentionned some fixes that would be usefull/mandatory.

• DMA pull-up on databus
• WD1772 pull-ups
• LMC audio mix fix
• RGB Video ghosting fix
• C415 that should be reversed

 

The projects contains an approximative reconstruction of the motherboard's PCB. It will be good enough to locate a given component and to know how a signal is distributed accross the board. And it allow to make nice 3D renderings.

[rustynutt]

Thank you for all the time That is a huge effort.

Just now starting to do a hand delineation of the Falcon COMBEL to PGA socket adapter, to connections, and Sparrow COMBEL PGA socket to connections. I'm staring at hours and hours of work

[Sporny Kun]

yep, and then seeing all those hours and hours coming together is greatly rewarding.

[Cyprian]

I wonder whether would be possible to squeeze the STE motherboard to the short ST size

[Sporny Kun]

It may be a little bit tight, but one may save some space by not supporting the external blitter and the modulator/composite encoder. On the other hand, one could reuse some ideas from Exxos's H5 like a modern RS-232 IC that does not require dedicated voltages converters, and using a single 72-pins SIMM.