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Creating a replacemant gate array

Started by Bread80, 18:11, 29 April 21

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eto

Quote from: Bread80 on 17:12, 10 July 21I now have the revision 2 development board.

Would you be willing to share your design? I am curious how easy or hard it is to use a Pico with the CPC...

Bread80

Schematics and software will certainly be open sourced. I'm haven't decided whether to open source the gerbers (when it gets reduced to a DIP-40ish size). In any case the PCBs won't be easy to hand assemble with the tiny components used.


I'm not sure what you mean about how easy the Pico is to use with the CPC. It needs level conversion for any signals into the Pico. The CPC uses 74LS chips so signal from Pico to CPC are okay as is. In software terms then it depends what you want to do with it. It's plenty fast enough to deal with a 4MHz Z80. (Things get tight with the 16MHz gate  array though).

genesis8

What's the current status Bread80 ?
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Bread80

@genesis8 , sorry for the slow reply.

I now have a smaller version which fits neatly into the DIP socket. It's using a pair of RP2040Stamp which is about as close as you can get to an raw RP2040 whilst still being able to hand solder.

There's still one or two issues with the board, and I need to finish updating the code be fully compatible with it.

I'll probably do another revision in this format before I try to miniaturise it.

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GUNHED

Thanks to keep us updated about your great advances.
http://futureos.de --> Get the revolutionary FutureOS (Update: 2023.11.30)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

genesis8

A slow one is better than none :-)

Thanks.
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TotO

"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

GUNHED

Quote from: genesis8 on 20:55, 14 May 23A slow one is better than none :-)

Thanks.
Sometimes thing look to be slow. But few know how much hard work is behind it.  :)
http://futureos.de --> Get the revolutionary FutureOS (Update: 2023.11.30)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

Bread80


Mine is a completely different design. No FPGA. All done with ARM processors. Probably a bit more technically complex, but far easier to reprogram and add extra features :)

Bread80


Although mostly because I've got far to many projects on the go to devote enough time to any single one of them.

Sykobee (Briggsy)

Those small ARM microcontrollers are really neat - fast enough to do in software what used to take hardware. Do you make use of the Pico's fancy I/O controllers to help with some of the video signal generation?

TotO

Quote from: Bread80 on 18:37, 16 May 23Mine is a completely different design. No FPGA. All done with ARM processors. Probably a bit more technically complex, but far easier to reprogram and add extra features :)
I know that. I mean about the integration, not the way to do it. :)
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

Bread80

Quote from: Sykobee (Briggsy) on 17:25, 17 May 23Those small ARM microcontrollers are really neat - fast enough to do in software what used to take hardware. Do you make use of the Pico's fancy I/O controllers to help with some of the video signal generation?

Yes, lots of PIOs.
The system signals are almost exclusively PIOs and PWMs - the only thing there using CPU core is when the RAM/ROM enable changes. (The code writes the new settings to a PIO).
The video uses CPU core for the pixel decoding and I/O. There's also a bunch of PIOs and DMAs involved. I'd like to rewrite the video to use exclusively PIOs and DMAs, but doing it that way is exceptionally complex.

GUNHED

Since you use PWMs ... could it theoretically be possible to add more colors?
http://futureos.de --> Get the revolutionary FutureOS (Update: 2023.11.30)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

Bread80

Quote from: GUNHED on 13:34, 18 May 23Since you use PWMs ... could it theoretically be possible to add more colors?
Video out is unrelated to the PWMs - they're just driving clock (etc) signals.

The video out is 8-bit RRRGGGBB, so 256 colour. There's a look up table in the code to convert decoded bytes to the CPC palette. So, yes, you could change the 'hardware' palette, or use additional colours.

One of my plans is to add an 'enhanced mode' for writing data to the gate array. That would allow you to access additional features beyond the standard 'command set'. The fun part will be making that compatible with the original firmware ROMs :)

GUNHED

That's great!!! I'm really looking forward to enhanced modes an will of course support them with my OS. Also for the Firmware it should be doable. The guys who created Firmware 3.x will surely be happy to add such features. If not a patch can be done hopefully in quick time.  :) :) :)
http://futureos.de --> Get the revolutionary FutureOS (Update: 2023.11.30)
http://futureos.cpc-live.com/files/LambdaSpeak_RSX_by_TFM.zip --> Get the RSX-ROM for LambdaSpeak :-) (Updated: 2021.12.26)

SerErris

Proud owner of 2 Schneider CPC 464, 1 Schneider CPC 6128, GT65 and lots of books
Still learning all the details on how things work.

Bread80

Quote from: SerErris on 21:44, 05 September 23@Bread80 any update on this?
Not much progress recently. I'm getting too carried away on other projects, including a couple of CPC related ones :) 

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