Raspberry Pi Pico Multicart - 2600PicoCart

[edelro]

@electrotrains

Do you have news for us?

[Himeno]

yeah i too want ask that

[captainmonobrow]

I've just stumbled upon this thread having been thinking for a while "wouldn't it be great if someone created a simple interface board to take a cheap pico with minimal components and the internal memory, so I could quickly and cheaply have a way to play homebrew games on my 2600 jnr".

 

@electrotrains - I appreciate your massive contributions to the community! Do you think you will pick this project up again, or has it come to the end of the road on account of the compatibility issue previously mentioned? If this is necro, do you think releasing the design files or at least the code for the pico firmware (even in its current state) would be of value? Your design is cheap enough that if it doesn't work for someone's application then it's no real drama (especially if they de-solder and reuse the pico).

[gtortone]

Hi,

I'm working on PlusCart porting for RP2040 (Raspberry PI Pico):

 

   https://github.com/gtortone/United-Carts-of-Atari

I started few weeks ago forking official PlusCart project. Currently the Pico emulates base cartridges files with support for ESP8266 uart-wifi bridge
and SD support.Now I'm working to add other cartridge types (SuperCharger, ...);

 

[SuperZapperRecharge]

3 hours ago, gtortone said:

Hi,

I'm working on PlusCart porting for RP2040 (Raspberry PI Pico):

 

   https://github.com/gtortone/United-Carts-of-Atari

I started few weeks ago forking official PlusCart project. Currently the Pico emulates base cartridges files with support for ESP8266 uart-wifi bridge
and SD support.Now I'm working to add other cartridge types (SuperCharger, ...);

 

Might want to take a look at this topic 

 

It only runs one game at a time. Currently @karri has 48K 7800 carts able to run from the Otaku board. At least there is a good code base to see what he has done.

[aotta]

I kindly ask @electrotrains if he could publish the 2600PicoCart working with Jr consoles, it'll made happy many users and we could made some further test for helping in find a solution for woody 2600.

 

P.S.: i used lot of your ideas and code for my Sega SD-1000 multicart (https://github.com/aotta/SD-1000) and it works very well, thank you again!

[philgood1351fr]

@aotta Great, got to test it quickly on my SC3000. Can you tell us the kind of diode you use and it seems the jumper on the right need a bit of soldering flux no ? What for ?

Thanks anyway.

[aotta]

16 minutes ago, philgood1351fr said:

@aotta Great, got to test it quickly on my SC3000. Can you tell us the kind of diode you use and it seems the jumper on the right need a bit of soldering flux no ? What for ?

Thanks anyway.

I used a 1n4148 diode, but it's only for avoiding overcurrent the Sega if the Pico is usb connected, so you can use different kinds of diode.

The jumper was in initial project becouse i wasn't sure of both SG-1000 and SC-3000 compatibility, then i found the jumper is not necessary and you must leave it open. But yes, i haven't desoldered very well my pcb after the tests! 😁 

p.s.: i used the same purple pico for a new Colecovision multicart, and also for the PiRTO II for Intellivision, you could find it on relative sections here!

Edited May 31 by aotta

[philgood1351fr]

Great.

 Thanks a lot man.

[dzo]

@electrotrains this is an awesome project, as a 2600 Jnr owner is love to put one together! Do you have any plans to return the project soon, or share the progress that's been made so far as you did with your other projects?

[Piaras93]

Hey Folks, I would love one of the 2600 picocart's . I bought 5 A8 Picocart's from PCBway and have just realised they wont work in a Atari 2600. I cant find the files for the 2600 Picocart to order one... Very new to this but does anyone even have one for sale or a link to buy one? Thanks!!

[tspfreitas]

On 5/23/2023 at 12:34 PM, electrotrains said:

Hi All,

 

I thought it was time to post about my latest mini-project - I've ported my original UnoCart 2600 code to run on a Raspberry Pi Pico which is a very low cost (£2-£4) ARM based microcontroller board from the Raspberry Pi Foundation in the UK.

 

The idea is to make a very low cost (<£5) DIY multicart project, which really just involves soldering a pico to a PCB - there are no other components.

 

In theory the pico requires voltage level shifters to connect to the 5V atari bus, but there are rumours to the effect that most of the GPIO pins are 5V tolerant (and in practice others have not encountered problems to date), so I've skipped them on the basis that this is supposed to be cheap and cheerful. I've been running it for many hours so far without problems, but your mileage may vary.

 

There is no SD card slot - the Pico has a 2Megs of flash, so I've written code to expose it as a mass-storage device when plugged into USB. In practice that means you can plug it into your PC with a USB cable and drag and drop files directly onto the cart from Windows. The 1meg of flash allocated to ROMs is in practice enough to fit all my favourite stuff and more.

 

The PCB supports both the cheaper castellated edge pico version which can be soldered directly to the board surface mount style, or the Pico H with headers.

 

The firmware is basically the UnoCart 2600 firmware, and I haven't finished porting all the cartridge emulation code yet, but it basically seems to work great, though I do get a noticeable amount of RF interference on the TV compared to the original unocart - I'm waiting for some new PCBs to arrive from China that will hopefully improve matters there. The new PCBs will also have mounting holes, and a PAL/NTSC solder bridge for selecting the firmware.

 

When I've finished the firmware, if anybody wants a finished cart to help me do a bit of testing?

 

Initial Prototype

 

Version 1 PCB

 

 

Pico-themed green firmware (Pal)

 

 

Atari XL/XE Version

 

I've also made an Atari 8-bit version using a purple 16Meg Pico clone that has more GPIO pins than the original Pico (the Atari 8-bit cartridge port has slightly too many signal lines to interface to the original pico). I'll post about that in the 8-bit section seperately.

 

 

What an incredible job, I arrived here by parachute and I see that the Rp2040 is more versatile than I expected hehe now following for news, do you intend to share this project as well as the Unocart?

[aotta]

I hope @electrotrains will come back soon, in the meanwhile i'm working on his initial project with some variations:

 

I didn't solved the issue he found in starting the cart (Atari bootstrap is faster than Pico's one, so it works only if pico is already powered when 2600 starts), so i'll add a coin cell rechargeable battery.

I'm adding the support for more bankswitching schemes, taking the code from Unocart (now pico2600 supports 2k,4k, FE and F6 type, and Atari 7800 8k,16k,32k e 48k), and looking for improve the code for starting selected game (not all games start automatically, for some i have to poff-pon the console: i'm afraid i've not fully understood how the "set_menu_status_byte" in Unocart's menu works! 😁).

I'll publish kicad and arduino source on my github as soon as i'll finished it.