PiColeco Do It Yourself Multicart for the Colecovision

A very interesting "Do it yourself" project was posted on the Atariage forum in the Colecovision section, by user aotta, which supplies information on making a flash multi-cart using a clone of the Raspberry Pi PICO, a simple circuit board and one diode. The parts cost is around $11 total, so anyone who can solder should be able to undertake this project.
I thought I would do a video showing my efforts at putting one together and go through the steps of how to set up the Raspberry Pi PICO and of course, try it out on real hardware.
#retro #gaming #colecovision #raspberrypi #pico #multicart
See the original forum post here:
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And the GitHub repository here:
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[@TheHighlander71]

Multicarts. Multicarts everywhere! It seems like loading software into consoles always has a few hidden secrets doesn't it? Over time engineers found clever ways of loading larger games. Cool little project and sounds very affordable.

[@electricadventures]

It’s definitely worth a try and I think this same technique could easily be adapted to a few other systems e.g. Spectravideo. I think someone already has done something similar for the C64.

[@markpayne2162]

Oh wow! This is in my video list as well mate. I'm doing the Atari A8PicoCart first though. Uses the same clone with the exposed extra pins. I am amazed at these brilliant low cost options. Easy to make for everyone which makes me enthusiastic to share them. Also... "scruffy"??? Rugged, mate, RUGGED!!!

[@electricadventures]

Well we say well traveled ;) I’m looking at improving the Pico code, the same code is doing the rounds between these projects, but now that the base format is working should be able to get it to support a lot more cartridges.

[@custardo]

Those purple pico's work great as a picoboot for the gamecube as well

[@electricadventures]

They are fantastic aren’t they I have to play with them some more!

[@jessragan6714]

Pick a peck of purple picos!

[@jessragan6714]

Okay, so let me get this straight. You don't have to connect your pico to an EPROM reader or anything like that? You just plug it into the USB port of your computer and hold down the reset button and it's recognized as an external drive? Niiiiice. I'm definitely interested in this now!

[@electricadventures]

Yeah you only hold down the button when you want to load a new version of the software. If you just want to load ROMs you just plug it into a computer and it will appear as a normal drive. But yes that easy. I’m going to see if I can improve the software so it supports ROMs larger than 32k.

[@chadkenzie78]

Great walk through video mate, what type of size/type diode is needed for this build?

[@electricadventures]

I just used a 1amp that I had on hand which is overkill, probably at least 200ma one would be fine.

[@martialalmac]

Looks great! I see on the gerber file and design there is a space for a switch? Is that required as well as the diode?

[@electricadventures]

The switch is so you can reset the coleco and get back to the cartridge menu (pressing the coleco reset button just resets the currently loaded cartridge). I didn’t have any so left it off and it works. I have some on order. Any diode is fine, the amp requirements are pretty low. The Pico build has been updated and now it supports a lot more rom images ie a fair number of larger than 32k ones.

[@abcnetgames]

excellent video!!! Are these files you use in this video available for purchase or something? I'm having trouble finding the correct files

[@electricadventures]

The main place to go is the GitHub page or the thread on Atariage. I’ll check which links I added to the video description a bit later.

[@electricadventures]

I just checked and both links are there in the description the GitHub one would be your best bet.

[@evocre8r]

Fantastic tutorial. I ordered all the parts soldered it all together. It connects to the PC just fine and I am able to transfer the firmware and roms. But when I put it in my colecovision, I just get the "power off and insert cartridge" screen. I tried flashing all the other firmware and tried it on two different consoles, but no dice. do you know what could be wrong? Thanks!

[@electricadventures]

I did find it very difficult to get it to work the first time as well as the solder pads on the PCB were very small. Reflow all of the connectors again and see. The fact that you can hook the Pi up to the PC means the Pi is still working.

[@evocre8r]

@@electricadventures Thanks, will do. What's odd is that if I put it in the coleco, the Led turns on. But it won't load. Then while the coleco is on, if I plug it into my pc USB port, it loads right up and plays fine as long as it's connected to USB. Strange.

[@evocre8r]

@@electricadventures you hit it on the head. I reflowed everything and now they work fine. Thanks for your help!

[@flynnz]

Thanks for the info Tony. How hard or involved is it to have the PCB made at PCBway? I saw the zip file on the github, but it contains so many elements. Do you just give that one zip file to PCBway and they make it for you? or is there more to it than that?

[@electricadventures]

Yep at the start of the PCB order process just upload the ZIP file and it will set most of the options for you. I found the pads a little small, but I probably should have used flux.

[@aotta1969]

I didn't use the pins included with Pico, but the rounded ones that i prefer

[@Evilslayer73]

Hi do i need absolutely the purple one with just one button ?because they sell a model on amazon with 2 buttons 16 mb purple color for gamecube modchip

[@electricadventures]

You will need to check the output pins on the board to make sure they are the same. The purple one is required as it has more output pins than the original one.

[@Evilslayer73]

@@electricadventures Thanks ! 👍

[@aotta1969]

Just to confirm that only 32k roms are supported, i did some test with bank switching and roms 64k and 128k, but without success at the moment... maybe someone could improve my project better than me!

[@electricadventures]

Yep I worked that out :) I will have a look at the code running on the Pico it is going to need to support the megacart switching scheme. Give me a week or so and I will work it out.

[@markpayne2162]

Bloody amazing work!!

[@aotta1969]

@@electricadventures i uploaded on github a firmware version (1.0a) supporting megacart bankswitching up to 128kb

[@evocre8r]

@@electricadventures Any updates? Just checking :)

[@electricadventures]

@@evocre8r the latest firmware supports a few more mappers and carts up to 128k, not 100% but a lot better.

[@MotownBatman]

But I Wanna Watch It Nooooow.

[@electricadventures]

Patience grasshopper ;)