Cartridge Port Read From SD Card

[KevKelley]

I was curious.

 

Is there a pinout for the cartridge port of the 2600+?

 

I have read where some have found that the 2600+ can load a game off a SD card in a Harmony if there is just one game loaded on it but I was wondering if there is a way to make a non-Harmony or non-Uno SD card cart (pardon my highly advanced technical speak 😂)

 

I was just curious if I can try and make a simple card with a sd card slot and save the .bin on it so the 2600+ would read as if it was a regular cartridge. Not looking to make a multi cart or anything and I imagine something like this wouldn’t be compatible with original hardware. I had thought this could be an inexpensive way for me to make copies of my games I make for testing or distribution but didn’t know if it was as simple as seeing which pins send or receive data and just connecting the corresponding parts. 

 

[Glorkbot]

Well, I’d sure like one of those, if it were housed in a cartridge shell.

[r_chase]

Somebody is working on it with a Raspberry Pi Pico.
https://forums.atariage.com/topic/357465-diy-2600-flash-cart-with-a-raspberry-pico/

[KevKelley]

20 hours ago, Glorkbot said:

Well, I’d sure like one of those, if it were housed in a cartridge shell.

That is what I was thinking. 

[KevKelley]

3 hours ago, r_chase said:

Somebody is working on it with a Raspberry Pi Pico.
https://forums.atariage.com/topic/357465-diy-2600-flash-cart-with-a-raspberry-pico/

I thought that was more of a multi cart using a Pi Pico for the method. I’ll reread the thread. 
 

I just didn’t know if the 2600+ was reading and just looking for a .bin and if it would be easy enough to just set up a sd card port and the tiny sd card to house a single .bin. 
 

I did a brief search the other day on lunch but couldn’t quite find what I was looking for. 

[r_chase]

Just now, KevKelley said:

I thought that was more of a multi cart using a Pi Pico for the method. I’ll reread the thread. 
 

I just didn’t know if the 2600+ was reading and just looking for a .bin and if it would be easy enough to just set up a sd card port and the tiny sd card to house a single .bin. 
 

I did a brief search the other day on lunch but couldn’t quite find what I was looking for. 

Well, I hope you find what you're looking for.

[Glorkbot]

8 hours ago, r_chase said:

Somebody is working on it with a Raspberry Pi Pico.
https://forums.atariage.com/topic/357465-diy-2600-flash-cart-with-a-raspberry-pico/

But I guess that won’t use .bin Instead it will use uf2 files that you have to create in python instead? Seems beyond my level of use.

Edited January 13 by Glorkbot

[+karri]

5 hours ago, Glorkbot said:

But I guess that won’t use .bin Instead it will use uf2 files that you have to create in python instead? Seems beyond my level of use.

@astroguy appears to be able to use a PicoW (wifi version) that may be able to beam over standard game files to the Pico flash. So there may be an easy way to send single game files from your phone to the Pico.

[ChrisKewl]

49 minutes ago, karri said:

@astroguy appears to be able to use a PicoW (wifi version) that may be able to beam over standard game files to the Pico flash. So there may be an easy way to send single game files from your phone to the Pico.

I'm excited about this cart if he gets this to work! Would be useful to do quick dev work on a game, just beam the updates to the PicoW and playtest.

[+karri]

Currently I do not own a PicoW. And it is €15.40 locally plus postage. So more than twice the price of an ordinary Pico. But I will follow with interest where @astroguy project is heading.

[astroguy]

5 hours ago, ChrisKewl said:

I'm excited about this cart if he gets this to work! Would be useful to do quick dev work on a game, just beam the updates to the PicoW and playtest.

I'll note that this is already possible with the current multicart design.  You can connect the Pico-cartridge and USB to computer at the same time.  On your computer you would compile your Atari ROM, then run a script that would create the Pico UF2 that includes the new ROM.  On the Pico you hit the reset and boot buttons that places the Pico into USB mass-storage.  Then dump the UF2 on to the Pico from your desktop.  The pico will automatically reboot and serve the ROM to the Atari. 

 

Some additional thoughts:  The Pico as 26 GPIO pins.  For the 2600+ with a 2600 ROM we need 8 for the data bus, 12 for the address bus and 1 for the chip enable (A12).  That leaves 5 pins.  I've used 4 of them connected to a dip-switch to select ROMS.  An alternative is to connect an SD-Card.  That needs 4 pins.  So we could use an SD-card to serve a ROM, but it's one at time as the 2600+ is only a dumper, so we can't use on-screen menus.   Of course, the SD-Card uses SPI so we could slave a display and we could potentially use the address lines when CE is low to add an interface to dive through menus.  So maybe.. but not today as the option above just seems messy and will not work for the 7800 as we need additional pins for the address bus.

 

I'm motivated to make the WIFI work.  The design already works with my current prototype and may also work for serving 7800 ROMs.  So now it's figuring out the software side.  I'll try to keep future conversation limited to the DIY Cart thread that away all this info can be found in one spot.