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  • Joined: 26 Feb 2021
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Colecovision to Master System adapter
Post Posted: Sat Oct 15, 2022 10:01 pm
Last edited by Apocalypse on Sun Dec 04, 2022 10:31 pm; edited 1 time in total
Uses the MS VDP in compatibility mode, hence slightly off colours.

Maintain the PAUSE button on the console to enter keypad mode: numbers are mapped to the D-pad using the same disposition they have on a Colecovision controller (if you picture it), e.g. up = 2, up + right = 3, etc.
That covers keys 1 to 8 (which is enough for difficulty and player selection in most games).
For the remaining keys: 1 + up = 5, 1 + down + left = *, 1 + down = 0, 1 + down + right = #, 1 + left = F3, 1 + right = F4.

[EDIT]Picture attached[/EDIT]

Here's a video of it in action, for now I'm using Colecovision ROMs on a MS cartridge PCB.

https://vimeo.com/760660538
Keypad.png (13.95 KB)
Keypad.png

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Post Posted: Mon Oct 17, 2022 8:33 am
this is very interesting! more details on how it works?
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  • Joined: 15 Jan 2018
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Post Posted: Mon Oct 17, 2022 9:14 am
This is mind-blowing! You're on fire.

Never thought my Master System could allow me to collect games for another system without owning the console. Love the idea bc retro consoles break much more easily than retro games, and take space too.

Is there any plans for launching this as a product?
Like your great Mark III to SMS adapter.
Feel free to do an MSX to SMS adapter too if you feel like it ;)
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Post Posted: Mon Oct 17, 2022 9:47 am
Oh mate, that is awesome!

sverx wrote
this is very interesting! more details on how it works?


Same! Initial guess along the lines of - Colecovision has a Z80 and a TMS VDP inside, but presumably different memory & I/O mapping, so somehow you are intercepting bus traffic and conditionally replaying to the SMS hardware where appropriate? If so, presumably only works if the I/O maps don't overlap.

No sound? Is it possible?
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Post Posted: Tue Oct 18, 2022 5:50 am
Jair wrote
This is mind-blowing! You're on fire.

Never thought my Master System could allow me to collect games for another system without owning the console. Love the idea bc retro consoles break much more easily than retro games, and take space too.

Is there any plans for launching this as a product?
Like your great Mark III to SMS adapter.
Feel free to do an MSX to SMS adapter too if you feel like it ;)

If there's enough demand for it I'll make a small batch. But since BIOS is copyrighted I'll need to rewrite the subroutines before I can include them.
I'm also working on a MSX adapter (MSX1 only).

sverx wrote
this is very interesting! more details on how it works?


willbritton wrote
Oh mate, that is awesome!

Same! Initial guess along the lines of - Colecovision has a Z80 and a TMS VDP inside, but presumably different memory & I/O mapping, so somehow you are intercepting bus traffic and conditionally replaying to the SMS hardware where appropriate? If so, presumably only works if the I/O maps don't overlap.

No sound? Is it possible?

That is exactly what it does, overlapping isn't a problem.
Sound may be a bit low in the video but is present.
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Post Posted: Tue Oct 18, 2022 1:02 pm
Apocalypse wrote
That is exactly what it does, overlapping isn't a problem.
Sound may be a bit low in the video but is present.

Ah sorry, I thought I had my sound turned right up but straining to hear, must be my old age ;)

Out of interest what's the big ol PLCC device we can see there?
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Post Posted: Tue Oct 18, 2022 8:07 pm
It's a CPLD from the ATF150x family, still manufatured by Microchip (formerly Atmel).
Clearly overkill for the job in terms of available I/Os and macrocells but has the huge benefit of being 5V compatible (in 2022!).
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Post Posted: Fri Oct 21, 2022 1:03 pm
Apocalypse wrote
It's a CPLD from the ATF150x family, still manufatured by Microchip (formerly Atmel).
Clearly overkill for the job in terms of available I/Os and macrocells but has the huge benefit of being 5V compatible (in 2022!).

Ah nice.

Tell me about it! Finding 5V compatible CPLDs has been a total nightmare for me, they seem to be increasingly rare and with the chip shortage it's so hard to know whether the supply will ever recover, and whether the unit cost will ever be sensible again...

I actually thought for some reason the 1500 series was 3.3v only but I see now it looks like it's only some of them (e.g. ATF1508ASV seems to be only 3.3v...perhaps it's the -V suffix that makes them low voltage?)

Thanks - that's one more on my small list of potentially useful devices!
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Post Posted: Fri Oct 21, 2022 9:07 pm
Yup, it's the V.

(Also, if you read the datasheets for the "V" series parts vs the 5V ones, the current consumption has decreased by 1/3 (i.e. 3.3V/5V) and the speeds have decreased similarly and the absolute maximum rating is the same as the 5V part. I'd be wary of taking a chance on blowing some up, but it's similar enough that I do wonder if there's a real difference)
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Post Posted: Sun Dec 04, 2022 10:23 pm
lidnariq wrote
I'd be wary of taking a chance on blowing some up, but it's similar enough that I do wonder if there's a real difference

Actually I recently discovered some of the AS (without the V) chips I had ordered back in 2019 from Mouser and with a datecode from 2018, were actually ASVs...
Too late to make a claim but weird enough to be mentioned, especially them coming from Mouser you can probably rule out some dodgy chinese tactics (remarking).
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Post Posted: Fri Dec 23, 2022 1:13 am
[If there's enough demand for it I'll make a small batch. But since BIOS is copyrighted I'll need to rewrite the subroutines before I can include them.
I'm also working on a MSX adapter (MSX1 only).]

I'm very interested in these potential future products.
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Post Posted: Wed Jan 11, 2023 9:48 am
Perfect fit!

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