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Connecting 7800 to PC

cross development connect pc serial parallel

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#1 leep OFFLINE  


    Combat Commando

  • 8 posts

Posted Mon Feb 26, 2018 5:05 AM

I have an Atari 7800 that I've modded for composite video. Now I'd like to start learning how to write software for it. I'm already familiar with 6502 assembly (from the NES), but will need to do a deep dive into the MARIA chip (so far, how you access this seems crazy! :-o) and any other idiosyncrasies of the 7800. My question is, after writing and compiling on the PC (Windows), is there a way to run/test what I write on the real hardware? Or am I limited to running/testing in emulators on the PC? Something like a cartridge with a serial cable connected to the PC where I could compile on the PC and update the cartridge via the serial cable would be wonderful... does anything like that exist? I just had a vision of a Raspberry Pi Zero W in a 2600/7800 cartridge case connected to the PC over WiFi... LOL!  :)

#2 Trebor OFFLINE  


    River Patroller

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Posted Mon Feb 26, 2018 10:52 AM

For programming the 7800 overall, the 7800 Development Wiki is very valuable. 


For Assembly programming specifically, the 7800AsmDevKit may provide benefit.  Understanding the MARIA chip and idiosyncrasies, among other items, the updated 7800 Software Guide is a great resource. A downloadable *.pdf version of that updated guide can be obtained from this post.  Some additional in depth specifics can be referenced under the 7800 Tutorials and Guides section of the Wiki.


Testing under real hardware can be managed by acquiring an MCP Development Kit, which connects via USB port from a computer to the second controller port of the console.  More tech details can be read from this post, including no modifications to the 7800 console are needed.


There is also the Mateos flash cart with instructions posted.  Another flash cart, called the Cuttle Cart II, has been out of production for many years now, and tends to be very pricey when a previously owned one does appear for sale.  In development for quite some time with several beta/test carts out in the wild, is the Harmony Concerto; no ETA on final product or mass availability.


In lieu of the above options, the console BIOS can be updated to DevOS as part of creating a complete dev environment.  There is an archive of Eckhard Stolberg's Atari VCS 7800 development system page available with respects to origin.  The Atari 7800 w/devOS BIOS working with modern PC's? thread can provide some guidance.  Also, see the 7800 Dev System mode question thread. 


Heads-up if going the hardware modification route with building a DevOS system, while several visitors of the forum reported having such a system built, the console chosen for the modification may wind up being finicky.  PC windows compatibility includes support from Windows 95 thru XP (32-bit), and it requires a parallel port.  The second revision DevOS files and documents/instructions can be downloaded here: Attached File  devkit2.zip   59.06KB   31 downloads


The next best thing, going outside of real hardware testing and utilizing software emulation instead, is A7800.  It is the closest to exact hardware emulation publicly available.  An easy setup guide for Windows has been provided.  Being a fork of the MAME project, it contains a pretty extensive debugger, easily launched via the '-debug' command line switch [I.E. 'C:\A7800>a7800 a7800 -debug'].



#3 leep OFFLINE  


    Combat Commando

  • Topic Starter
  • 8 posts

Posted Mon Feb 26, 2018 11:36 AM



Thank you for the very prompt and very information-rich reply!  I'm at work at the moment, but will pour through these references this week after work hours.  Again, thank you very much! :)

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