Atari 2600/7800 Flash Cartridge

[electronrancher]

Hi All,

 

I got a mention that there is more interest in a 7800 flash cart than a 2600 flash cart, so I am reposting about my flash cart here.. Hope noone minds the duplicate!

 

I built up a little flash EEPROM module to replace the EPROM in a gamewiz development cartridge, and wanted to see what you guys thought of it.

 

Basically it's built out of a 29C512, flashed with any standard EPROM programmer, and is split up into 8 banks of 8k each. For the 7800, this can be reconfigured to 4 banks of 16k, or 2 banks of 34k each, and still fit in a standard 28-pin EPROM socket. Just flip the DIP switches to swap between banks - it's really cool to have 2-3 revisions of a game or something right at hand and hop between them when debugging.

 

Anyway, I wanted to see what kind of development cartridge people were using - I love the gamewiz, but man - non flash EPROMS are tedious to burn and erase, even if you have a bunch of them! This thing can flash all banks in about 10 seconds in my needham's programmer. I am currently working on a cheap parallel port programmer (about $25 USD) for the users who don't have a real eprom burner on hand, and don't want to shell out $250 for one!!

 

If anyone is interested, I built a bunch of boards (minimum quantity, but still painful!) and have them all populated with flash. Finished a few modules so far, but I have plenty left! I can configure the board as 8 banks of 8k, or 4 banks of 16k for the 2600, or as two banks of 32k for the 7800.

 

The pictures are also up on my ebay page.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...me=STRK:MESE:IT

Edited March 6, 2006 by electronrancher

[supercat]

Looks somewhat cute. Not sure how that form factor compares in usefulness with using the normal cartridge form factor plus a programming header. Nice job soldering the surface-mount parts, though. What'd you use to do that?

[electronrancher]

I got them mounted with IR reflow - basically a pick & place, then a run through the IR oven. Not cheap, but is it nice for aligning those 0.5mm lead pitches.

[supercat]

I got them mounted with IR reflow - basically a pick & place, then a run through the IR oven.  Not cheap, but is it nice for aligning those 0.5mm lead pitches.

1028415[/snapback]

 

Yeah, that's the "standard" way to do things, but I was wondering if you had any magic to do it cheaper.

[electronrancher]

If you were only doing one or two, you may be able to do it with a soldering iron, but it depends on how much skill (practice) you've had on fine-pitch devices. I did swap one '512 for a '010 by hand, but I had a hot air station to remove the old one, and a nice magnifying glass/lamp to look through when installing the new one. All I can say is it took a lot of flux, and it's important to get it aligned perfectly. Solder one pin at each corner to tack it down, and soak the pins in a lake of flux to prevent solder from jumping traces. Use about 10x less solder than you think you'd need, and that's just a little too much. Other than that it's not too bad..!

[Bruce Tomlin]

Here's a link to an article on sparkfun.com about an interesting and cheap way to do SMD solder reflow. They've got lots of crazy stuff in their Tutorials section. For the truly hardcore, they also have an article showing how to use a solder paste mask.

[electronrancher]

Now that is awesome! I like the boards they were building in the tutorials on reflow & paste stenciling - I was going to mention in my last post that the hardest package to hand-solder is a QFN, and there you go - right on the page in living color!

 

Maybe I should get me a Target brand electric skillet to fab my boards - lol! I bet that thing stinks though when you get it going!

[Curt Vendel]

Thats a very cool webpage, I love it - put another board on the barby!!!

 

 

 

Curt

 

Here's a link to an article on sparkfun.com about an interesting and cheap way to do SMD solder reflow.  They've got lots of crazy stuff in their Tutorials section.  For the truly hardcore, they also have an article showing how to use a solder paste mask.

1028752[/snapback]

[electronrancher]

So for all you fine folks with no eprom burner, I've worked out a parallel port writer for the flash cart! It can be built for about $5 USD, containing only 2 cd4040 binary counters (or equivalent), an LPT connector and DIP-32 socket.

 

Since mine is top-notch (haha!) , it also has a 7805 5v regulator to create the Vdd supply from my eprom programmer's 12v wall wart - you may have a 5v adapter lying around so you can use that instead.

 

Here are some pics, the schematic, and the flasher software if you want to build your own - I will post new software here, so feel free to report any bugs or discuss your development here! MMM Look at that cozy ratsnest! lol - not too bad actually, it's only 8 data & 13 address.

 

For those who are trying out the flasher software - put winio.dll in your system32 directory, it allows direct port access for the software. You can read about winio.dll here if you're wondering.

http://www.internals.com/

Flasher_Schematic.pdf

Flasher_v1.0.zip

Edited March 8, 2006 by electronrancher

[electronrancher]

New revision - I found that writing the carts with a normal EPROM burner enabled SDP - software data protection. The old rev can only flash virgin carts, this rev allows you to remove SDP as well as verify a cart against the buffer data. Additionally, you can choose between loading one bank as a C64 (8kB), or loading the whole chip as a C512 (64kB).

Flasher1.2.zip

Edited March 9, 2006 by electronrancher