A8PicoCart - UnoCart on a Raspberry Pi Pico

[electrotrains]

@mytek no problem.

 

looking at the pico code, X to disable the picocart just sets RD4/5 low, then goes into an infinite loop. On the 6502 side it sents a message to the cart to do the above, then does a cold restart (jmp $E477).

 

Its not clear to me at the moment why this would cause a problem.

 

Edit - I see @Wrathchild posted similar. thanks!

Edited October 10, 2023 by electrotrains

[+mytek]

2 minutes ago, electrotrains said:

@mytek no problem.

 

looking at the pico code, X to disable the picocart just sets RD4/5 low, then goes into an infinite loop. On the 6502 side it sents a message to the cart to do the above, then does a cold restart (jmp $E477).

 

Its not clear to me at the moment why this would cause a problem.

I'll need to take my XEGS out of mothballs and see what my original UNO Cart does when selecting the built-in game to boot.

 

Schematics coming...

[+mytek]

So I couldn't find my XEGS that was in a case, but I did find an XEGS motherboard that was missing all its chips. After replacing chips and burning a new MMU and OS ROM for it everything worked in the stock configuration. Powering up with the keyboard attached brought me into Basic, and powering up with SELECT pressed took me to the game.

 

So I don't have an A8Pico Cart, but I did have an UNO Cart, and plugged that in. If I started the console it took me to the UNO Cart menu. Pressing 'X' exited and took me to Basic. Next I shut it off, pressed SELECT and turned it back on. UNO Cart menu once again as expected, however pressing 'X' took me into Basic and not the game. A little bit different than what I was seeing on the 576NUC+. Then I thought wait a minute! Let's try pressing 'X' while in the menu, but first press and hold the SELECT key. Up comes the game. Of course this would be the case, since pressing 'X' causes a reboot, and without the SELECT key being held it defaults back to Basic.

 

So it looks like I need to see if I can adjust my TK-II firmware in the NUC to automatically do something like this, and then all the slots should be workable.

 

EDIT: I just hooked my 576NUC+ back up, and ran a similar test. So after powering-up with ALT+3 (Slot 3: Editor/Assembler selected) we entered the A8Pico Cart menu as expected. Then I pressed and held SELECT (F3 on the PS/2 keyboard) and then pressed 'X'. Sure enough the Editor/Assembler came to life

 

Slot 3 and Slot 4 require the game enable bit on the MMU to be low. This won't happen upon rebooting if the SELECT key isn't being pressed.

[Retrocactus]

20 hours ago, MVladimir said:

Please post this edited STL.

Here is the edited front cartridge shell without the logo 'cutout'. I realized after I had edited via TinkerCAD that the SCAD file was included and I could have done it there.

a8pico-front-no-logo.stl

[manterola]

On 9/24/2023 at 7:58 PM, Wrathchild said:

 

 

Anything UNO can do, PICO can equally do 😃

 

I have a UnoCart with updated firmware and just like the official last firmware it does not work in Atari 800.

So my questions are:

1.- Since A8PicoCart is based on UnoCart firmware, is A8PicoCart also incompatible with Atari 800?

2.- If that is true?, what is needed to make it compatible? Is it the Atari interface part (the menu) that is using calls that only the XL/XE OS has?

 

I am working in a PCB board for the brown Atari case, and therefore, if compatible with the 800, I won't need the reset button, and the deal with the USB back powering to MMU, so it should simplify the design.

 

[satoayanami]

It would be wonderful if you share your project, many people don´t like difficulties and buy a made cartridge by a little manufacturer, like the ATARIMAX, many other people like me, love the process of building something; i don't own the habbilities for designing and programmig a project like this, but i can build one with my ow hands. So, i'm excited about your reply to @popmilo; and i'll be waiting patiently, thank you in advance.

[xrbrevin]

2 hours ago, satoayanami said:

It would be wonderful if you share your project

it is already shared here:
https://github.com/robinhedwards/A8PicoCart

🙃

[bfollowell]

3 hours ago, satoayanami said:

It would be wonderful if you share your project, many people don´t like difficulties and buy a made cartridge by a little manufacturer, like the ATARIMAX, many other people like me, love the process of building something; i don't own the habbilities for designing and programmig a project like this, but i can build one with my ow hands. So, i'm excited about your reply to @popmilo; and i'll be waiting patiently, thank you in advance.

 

Read through the whole thread. He has already shared the project and all pertinent files on Github. I built ten of them a month or so ago and sold off all but the one I was keeping for myself.

 

[satoayanami]

3 minutes ago, bfollowell said:

 

Read through the whole thread. He has already shared the project and all pertinent files on Github. I built ten of them a month or so ago and sold off all but the one I was keeping for myself.

 

Yes, thanks, i noticed about that after posting my reply.

[bfollowell]

58 minutes ago, satoayanami said:

Yes, thanks, i noticed about that after posting my reply.

 

It was a cool, simple little project. I'm referring to the building, of course, not the design work! I wish I had the skills, and the time, to design things like this.

 

[ascrnet]

I share a new version of the firmware, it contains the latest changes of @electrotrains and also support for 3 more cartridges, these are :

* Standard 2k cars (CAR type 57)
* Phoenix 8k cars (CAR type 39)
* Blizzard 4k cars (CAR type 46)

a8_pico_cart.uf2

 

Regards

Edited October 22, 2023 by ascrnet
vignettes

[dmsc]

Hi!

 

To test the A8PicoCart firmware in real hardware, I decided to build one "on the cheap", and ordered two pico boards from Aliexpress at USD 1.80 each. My plan was using one of-the shelf 4x6 prototype PCB that I have, like this: 

But, I discovered that the rows don't align with the Atari cartridge connector :

 

 So I used a very old PCB for an 16KB cart that I had. Sadly, not all pins were present, so I cut and glued some copper pieces to add the missing pins (phi0, R/W, CCTL), and cut the traces connecting RD4 and RD5 to VCC:

 

After this, it was time to solder all the pins to the PICO board, and using some tape to keep all together:

 

It is ugly, but it works!

 

So, IMHO, this is the cheapest multi-cart you can possibly build for the Atari 8-bit.

 

Have Fun!

 

[+mytek]

2 hours ago, dmsc said:

It is ugly, but it works!

I had to laugh when I saw your creation, because it reminded me of so many of my earlier projects back when PCBs cost an arm and a leg. Now days even when prototyping I rarely ever do any point to point wiring on a bread board, and just go the manufactured PCB from China instead. They're getting so cheap to have made that it's hardly worth the trouble to hand wire something together. Because even if there are mistakes, just do a few tweaks in the layout and then for another few $$$ I'm done with a lot less pain.

[xrbrevin]

3 hours ago, dmsc said:

It is ugly, but it works!

Frankenstein cart! 🙃

[mimo]

9 hours ago, dmsc said:

So, IMHO, this is the cheapest multi-cart you can possibly build for the Atari 8-bit.

If you factor in your time for making it, then it's probably one of the most expensive.
I admire your dedication and skills though 👍

[+David_P]

Anyone doing cart port experimentation should order a bunch of these:

 

http://atariage.com/forums/topic/236819-xlxe-cartridge-slot-breakout-pcb-board-file-spares-available/

 

https://oshpark.com/shared_projects/wsJBXURh

[manterola]

On 10/16/2023 at 7:18 PM, manterola said:

I have a UnoCart with updated firmware and just like the official last firmware it does not work in Atari 800.

So my questions are:

1.- Since A8PicoCart is based on UnoCart firmware, is A8PicoCart also incompatible with Atari 800?

2.- If that is true?, what is needed to make it compatible? Is it the Atari interface part (the menu) that is using calls that only the XL/XE OS has?

 

I am working in a PCB board for the brown Atari case, and therefore, if compatible with the 800, I won't need the reset button, and the deal with the USB back powering to MMU, so it should simplify the design.

 

I just have tested A8PicoCart with my own PCB for the brown classic cartridge case with the latest firmware. I used a dirty and a bit rusty old Basic cartridge.

I can confirm that it does not work in A800. At least not in mine. This is an almost Stock A800 with the mod suggested in this post:

WUDSN - 8-bits are enough - Atari 800 Fix

 

The cartridge works fantastically in my Atari 600XL with 64KB mod. It is a really wonderful little project for DIY inclined people to perform.

 

I downloaded the ASM for the Boot ROM for A8PicoCart and with my limited experience with assembler I am trying to find some call that may be causing the problem with the non-XL machine.

 

 

Edited November 3, 2023 by manterola

[+scorpio_ny]

31 minutes ago, manterola said:

I just have tested A8PicoCart with my own PCB for the brown classic cartridge case with the latest firmware. I used a dirty and a bit rusty old Basic cartridge.

I can confirm that it does not work in A800. At least not in mine. This is an almost Stock A800 with the mod suggested in this post:

WUDSN - 8-bits are enough - Atari 800 Fix

Could it be because the Atari 800 does not have PHI 2 in the cartridge slot like the other computers? Here is a post that discusses this topic.

[The Mr. Video]

I just soldered everything and installed the firmware today, tested it out, and for some reason, my 600xl acts like I'm holding the option key down with no cartridge inserted. I know it's not the computer's fault because it loads normal cartridges just fine even after trying to use the pico cart. Is this something I should be worried about?

Edited November 3, 2023 by The Mr. Video
Clarification.

[manterola]

1 hour ago, scorpio_ny said:

Could it be because the Atari 800 does not have PHI 2 in the cartridge slot like the other computers? Here is a post that discusses this topic.

I thought about that, so I made the modification to feed in Phi2. The lack of Phi2 was not the problem, it still crashes...

[bfollowell]

44 minutes ago, The Mr. Video said:

I just soldered everything and installed the firmware today, tested it out, and for some reason, my 600xl acts like I'm holding the option key down with no cartridge inserted. I know it's not the computer's fault because it loads normal cartridges just fine even after trying to use the pico cart. Is this something I should be worried about?

 

I had a similar problem a few times. Well, not the exact same problem I guess, as mine would occasionally boot into basic. It was only before I installed it in a case though, as the problem was that there was a little play between the PCB and the cartridge slot of the machine I was testing it out on. If it wasn't lined up just perfectly, the machine would boot and not even see that cartridge as there. I'd have to move it and line it just right, then reinstall it. I've had no issues whatsoever since installing it in a case.

 

[manterola]

5 hours ago, manterola said:

I thought about that, so I made the modification to feed in Phi2. The lack of Phi2 was not the problem, it still crashes...

The A8PicoCart worked in my Atari 800 (OS-A)!. After pressing System Reset key I get the pink/purple menu every single time. The reset button in the cart does not work, which is not important if you use the cart with the A800 door closed. I was able to run a .CAR file.

It is not stable at all, thought. It keeps crashing while browsing the file system, or using the search feature.

But if you get to the point of selecting a ROM, it works..

 

[The Mr. Video]

13 hours ago, bfollowell said:

 

I had a similar problem a few times. Well, not the exact same problem I guess, as mine would occasionally boot into basic. It was only before I installed it in a case though, as the problem was that there was a little play between the PCB and the cartridge slot of the machine I was testing it out on. If it wasn't lined up just perfectly, the machine would boot and not even see that cartridge as there. I'd have to move it and line it just right, then reinstall it. I've had no issues whatsoever since installing it in a case.

 

I can't seem to get mine to work at all no matter how many times I reposition it. Meanwhile, I also tried loading a regular Atari cartridge board and got those to work without having to move them too much.

Edited November 4, 2023 by The Mr. Video
Added pictures of my work in case there's something I'm missing.

[pirx]

it works ok in my 800. i do have incognito.

[mozzwald]

1 hour ago, The Mr. Video said:

I can't seem to get mine to work at all no matter how many times I reposition it.

Your solder joints aren't the best looking, maybe some are not connected. Put flux on all of the pins and reflow the joints again. Also looks like there are solder blobs stuck to the board. Clean it off with alcohol and q-tip/toothbrush after soldering. You don't want metal bits falling into your Atari.