Viso

I think I'm about finished designing the next board revision. Hopefully this time it won't take three weeks to get the new boards. I'm going to spend some more time making sure there aren't new problems before ordering. Yes. The game must have code that supports the module in ordered for it to save any data to the module. Avoiding that limitation is unfortunately much more difficult and maybe even impossible.Great sig, btw. :-)

It can be used to save progress, but the game must support saving and restoring. For games that don't support the module, the controller pass through will be active the whole time. Also, the module keeps a simple file system to make it easy for multiple games to save data. I'm hoping this will make it easier to produce games that have such large scope as the popular Mario games on the NES. I have seen some old games get around the problem by presenting a screen full of text that the player must record and re-enter to continue later. That seems like a major bother. This is the first I've heard about the AtariVox device. I can't find much information about it on the web. The only image I found looks like it has a serial EEPROM that seems to be directly connected to the controller port. Is that right? Anyway, I'm not very close to having console to console communication working. The firmware wasn't made to support it, and the hardware I put together cannot handle it. I did think about it, and it would definately be a new and different project requiring more design work and testing. Because of other things I have to spend time doing, I'm not going to get the chance to start a new project for at least 6 months, but I think I can find the time to make a few modifications to my existing board design and test it over the course of 2 months or less. But, when I can spend the time on it, I could make a cool communication gizmo. I'm thinking a simple network between 2600's, 7800's, and PC's may be possible. It'll be a while, but it'll be better than just a couple of 2600's talking to each other.

Right now, the module cannot be used to enable communication between two 2600's or between a 2600 and a PC. The reason is that I used the same USART on the microcontroller for communication with a 2600 and with a PC. It let me pack in more functionality without having to add more components or a larger and more expensive microcontroller. I figured I should make it as inexpensively as possible yet robust, so anything other than memory module functionality had to be cheap to add. For instance, the playstation controller interface needed a connector and two resistors; everything else is software. The design gives dual purpose to several pins on the microcontroller and every pin is used for something. In better news, I designed the serial protocol for communication with the 2600 to support different devices on the same controller port. So if/when I do make a module for 2600 to 2600 or PC communication, that device could be connected along with the memory module on the same port. As for the pass-through connection, it has been working well. I designed it to work with all the 2600 controllers for which there were schematics for on AtariAge, and with the 7800 joystick. All have have to test with, though, are joysticks and a keypad.

I'm working on a project that I think some homebrew games could benefit from. It is a memory module for the 2600 and 7800 that allows supporting games to save data for later retrieval. I think it could help new games that need a long running game from start to finish because the hardware to save the game could be my module instead of some stuff on a special cartridge. The module provides a fairly easy to use interface for the game software and takes care of a file system so that multiple games can use the module. I've already made the first attempt at a PCB for the module, but I botched a few things. I hope to have a revised PCB design within a week, and hopefully I'll find time to populate and test the new board within a couple months. The firmware seems to be fine -- it passes all the tests I made for it -- so it is probably final. It plugs into a controller port, has a controller pass-through connector, a serial connection for access from a PC, and a Playstation controller connection (requires special cable) for emulating a joystick (great for 7800 games). Just wanted to see how much interest there was. You can find all the details at: http://home.hiwaay.net/~jeffj1/projects/amm/index.html Have fun!

I don't know where I read that 56KB number for the ROM. Did seem rather strange. Anyway, with 4KB ROM and everthing else, the 7800 must have more than 65592 bits lurking within its hardware.

The 7800 has certainly got more than 8 bits -- it has a whole 4KB of RAM. Thats 32768 bits and still doesn't include the ROM (56KB? that would be 458752 bits) or registers on the various chips. Sure, it has an 8-bit processor, but the processor has more than 8 bits. It has several 8 bit registers (A, X, Y, S, P) and must have a 16 bit instruction pointer. That totals 56 different bits. I've never programmed for it; I'm sure someone else can give a better number.

Thanks Tsukasa! They're not really cheaper per board, but I don't need 4 or 5 to test with. The lower minumum should cut the total cost in half.

Now that I'm getting fairly close to having what looks like a good layout, I'm going to need to send that layout to someone who can make a nice 2 layer PCB. I've made single layer boards, but 2 layers is a bit beyond what I can personally do. Who will make a board inexpensively for me? So far, it looks like http://www.pcbfabexpress.com is the best choice. Thanks for the help!

Thanks for the input; I have a much better idea of how to proceed now. I picked up what seems to be the Serpac 131 enclosure so I can get a better feel for its shape. I was planning to use the Serpac 032, but I think the board shape and layout will be identical. I'm going to fit the 7805 and a common power connector (needed to power the gizmo while connected to a serial port). I realized I can make the board a bit larger, so I think it won't be a problem. While I'm at it, I'll try to get the placement of the DB-9 connectors right.

Sounds pretty cool. Right now the only thing I can think of is having a few new useful bank switch modes possibleYes. It would be very nice to have some new modes so that if someone wants to write a large and ambitious 7800 game, they could. I just started playing Final Fantasy Tactics and was thinking that a game with similar mechanics might be possible. Now I just need more time . . .

From what I can tell, it looks like it is made so that 2600 games cannot use the dual 7800 buttons. Enabling those buttons is done with output the 6532 chip found in both the 2600 and 7800, so if a 2600 game could use the dual buttons, it probably wouldn't mean to since it would have no effect when the game is run on a 2600. That would have made for a bad compatibility issue. If you're considering changing the games' code, here's an idea: see if you can make it into a 7800 game. I remember seeing that there are safegaurds to prevent a 2600 game from enabling the Maria chip, but there may be no similar safeguard against a 7800 game that wants to disable it in favor of the TIA. Probably not quite that simple and I don't know that it can be done, but its the best solution I can think of short of changing controllers.

I'm designing a board for a new gizmo -- a memory module for the 2600 and 7800 (see http://home.hiwaay.net/~jeffj1/projects/amm/index.html). I haven't before made a board that I intended to put into some enclosure to make it a pretty gizmo in a box, so I'd like some advice. The gizmo has 3 DB-9 connectors, a cable to connect to the game console, and maybe a power connection. I was figuring I'd use PCB mounted right angle DB-9's. Is this a good idea, or would it be better to have a ribbon cable connected to the board? I've also been positioning the DB-9's to hang off the edge of the board a little -- good or bad? Right now, I've managed to fit it on a 3x5 inch board. I can put it on smaller boards, but I haven't been able to fit all 3 DB-9's on anything smaller in an enclosure that I know about. Also, I'm not using any surface mount components because I lack the soldering skill to work with those. Should I go for surface mount? Are there any good enclosures I should consider? I've got the gizmo set up with a controller pass-through port. The first 4 pins of the controller pass-through port are put through a 4016. I did this so that the module could disconnect the pass-through port to prevent joystick motion from interferring with memory module communication. I haven't done any stress testing on this. Can a 4016 handle the current going through an Atari joystick? If a 7805 is always connected to the +5v power line but isn't always supplying the power -- the +5v could be there while the Vin pin is left floating -- will the 7805 be damaged? Thanks for any advice, and have fun!

I've been working on a solution to having battery-backed RAM on a cartridge. It is a memory module that connects through a controller port, and a controller can connect through it so it doesn't need a dedicated port. It has a simple flie system so multiple games can share the storage. I'm going to start work on the board for what I hope will be the finalized version of the hardware soon. You can see more details on the page I made for it: http://home.hiwaay.net/~jeffj1/projects/amm/index.html

I wanted more manuals for the 7800 games that I haven't played much, so I started formating manuals for the games that didn't yet have a 40 column manual. I need to redo from M to later in the alphabet. I also formatted a manual for Solaris. The HTML manual on Atari Age is messy, so I tried to fix that. Enjoy! (Or don't) moremanuals.zip

The major pain is making good connections to the 7800's board. Everything else I had to do was much easier.