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Happy_Dude

7800 dev

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I picked up my first 7800 yesterday for the sole purpose of turning it into a

dev system. Mainly for 2600 stuff but I'd like to get into 7800 programming in

the future.

Anyway, is there a "PAL 7800 modding for idiots" text somewhere ?

I'v never had much luck with moding "gaming" stuff. :o

 

I'v checked my system and it seems to have a socketed bios EPROM.

I take this to mean all I need is a EPROM of the dev bios and a cable.

But as always it just "CAN'T" be that simple.

So if anyone can help out ... :)

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The current version of the DevOS text only describes the modification of a NTSC 7800. For the PAL model it is indeed as simple as replacing the EPROM chip. If your console comes with a masked ROM instead, you'll also have to find the jumper at W6 in the lower right corner of the board and move it into the free spot at W5.

 

To use this system for developing games you'd also need a RAM cart and the transfer cable of course. But building those is nicely described in the DevOS text.

 

 

Ciao, Eckhard Stolberg

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The current version of the DevOS text only describes the modification of a NTSC 7800. For the PAL model it is indeed as simple as replacing the EPROM chip. If your console comes with a masked ROM instead, you'll also have to find the jumper at W6 in the lower right corner of the board and move it into the free spot at W5.

 

To use this system for developing games you'd also need a RAM cart and the transfer cable of course. But building those is nicely described in the DevOS text.

 

 

Ciao, Eckhard Stolberg

I'm pretty sure its an EPROM but how do I tell if its a masked rom or not ?

 

Also it looks like a Resistor is meant to go at W6, just want to make sure that's what you where talking about ;)

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I'm pretty sure its an EPROM but how do I tell if its a masked rom or not ?

 

Also it looks like a Resistor is meant to go at W6, just want to make sure that's what you where talking about ;)

 

If it has a sticker over a little window on the chip, it's an EPROM. If it doesn't then it's a masked ROM.

 

The jumper at W6 probably looks like a tan resistor with a black stripe, right? That's the jumper Eckhard was talking about.

 

Mitch

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Ok the jumper is already on W5 :) and the BIOS "is" an EPROM :D

Making a cable will be a snap ;) and once I find a 7800 cart the RAMcart won't be too hard.

But burning the rom will be the tricky bit.

I haven't got a eprom burner yet so could anyone burn me a chip for cost ? :)

 

I plan on getting a burner in the future but as always money is the problem :(

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Yeah modding mine was a simple EPROM swap-out. I had a sneaky "it can't be THAT easy" suspician, too, but it was fine. Fortunately for me, the line of work i'm involved in enables me access to EPROM burners... I would offer to burn one, but I'm sure it would be quicker and cheaper for someone on the same side of the planet to do that for you ;)

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Hi Happy_dude, hi Eckhard! and everyone else!

 

I'm in Victoria, and will happily send you a DevOS v0.2 eprom for $8 incl postage. If you'd like to email your details we can work it out.

 

BTW, good luck! The 7800 dev system is something everybody should have, it's great!

 

cheers ......... gp :D

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What do you need to replace the OS ROM for? I thought the only obstacle it posed was it checked for the appropriate signature in the game's ROM.

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doppel:

The replacement ROM contains some extra routines that allow you to transfer data between one of the 7800 joystick ports and your PC's parallel port. If you'd also build yourself a cartridge with RAM on it, you could write 2600 or 7800 games on your PC and then quickly test them on the real console.

 

Graham:

Nice to see that the 7800 dev system provided you a reason to finally post around here again. ;)

 

 

Ciao, Eckhard Stolberg

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I got the EPROM today and I can make the cable tomorrow, but the cart will take some time (ie: I have no 7800 carts)

 

Can you just load a program into internal RAM ?

 

I cant wait to test it out :D

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Can you just load a program into internal RAM ?

 

A typical 7800 game is 32K or more, while the 7800 has 4K of internal RAM. RAM also gets used to build the sprite display lists for the MARIA GPU.

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Can you just load a program into internal RAM ?

 

I cant wait to test it out :D

 

I have a DOS program on my website, which allows you to create TIA sound effects on the PC and play them on the TIA in the 7800. This program can work with the internal RAM inside the 7800 and might be a good test if everything is working properly. Also you can of course use the 7800 to read out the ROMs from all your obscure Australian PAL 2600 games and play them on an emulator. ;)

 

As Eric already said, the RAM in the 7800 is probably too small for a usefull 7800 progam. Especially since the transfer routines are living in the RAM as well and shouldn't be overwritten during the transfer. ;) You can't use the internal RAM for 2600 programming either, because it gets turned off, when the console gets switched into 2600 mode. But if you are really having trouble finding 7800 games, you might want to contact Graham again. He has designed a lot of 7800 RAM carts to use with the DevOS and might be able to provide you with a nice RAM cart for 2600 programming.

 

 

Ciao, Eckhard Stolberg

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I realised most of my Australian exclusive titles where just HES multi paks

and AA has agreed to pull all the Activision roms. That includes the whole HES library :( (so I won't post any of them ;) )

 

Find attatched a dump of "My Golf" from HES :D

The only original game they released for the 2600.

 

I checked the rarity guide and this game is sadly missing.

 

 

p.s: I don't know whats happening with AA's attatchment feature just save the attatched file as a ZIP file

 

http://www.atariage.com/forums/files/2352_..._1057658535.gif

post-2352-1057658679.gif

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8) Just last week I found an old 7800 at a local fleamarket. I was

glad because over here where I live 7800 systems are very hard

to come by. It'll be my second 7800 console because I'd hate to

try and make a dev system and mess my only good system up. As

soon as I get a good understanding on 7800 game development,

I'm turning the second system into a dev system. ;)

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woo hoo. I found another padded envolope in the mail today.

It had 2 7800 carts. one of them was "Jinks".

Just what I needed a PCB No.C300565-XXX :D :D :D

 

Do I really need to use a "NEW" 74LS02 if I can remove the old one ?

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Do I really need to use a "NEW" 74LS02 if I can remove the old one ?

 

Well, you can, but it's possible for it to become damaged when you remove it. It's usually safer to just use a new one.

 

Mitch

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I'v used Jinks to make a 32k (?) ramcart.

I'v made the cart but it dosen't work, when I upload a rom and select 2600

game I get a screen that looks like the cart isn't in properly.

and with 7800 roms I get a blank screen.

 

Are there any pictures of this ramcart board somwhere?

theres just one jumper from pin 20 of ram to pin 13 of the 7402.

I'v read the instructions and am "really" sure that I got it right but it doesn't work :x

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Don't worry I got it working :D

32k DEV CART USING EXISTING RAM CHIP:-

 

RAM pin 20 (CS-) is connected by a single trace to U4 pin 3. (This is

the only trace connecting to U4 pin 3). Locate this trace on the back  

of the PCB in the vicinity of U4 and cut or file it through. Jumper RAM

pin 20 (CS-) to U3 pin 13.

looks like Graham counted backwards ;)

it's pin 4.

Now I have to go fire up the soldering iorn "again".

 

 

Woo Hoo I did it, I finaly have a 7800 development system :D :D :D

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My gaming mod luck returns :roll:

It's not working right .

My colour test demo works ok for some reason, but any comercial rom won't work :?

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Summer Games and Winter Games usually have a 32K RAM chip of which only 16K are used for the game. So performing the modification, that you quoted from, will give you a 32K RAM cart. Jinks on the other hand only has 8K of RAM, so the modification will only give you an 8K RAM cart at best. I'm not quite sure how these 8K would be mapped into the 7800's address space. But you can find out yourself by writing a ROM image to the cart and then read it out immediately with forcing the type to -t7832 or -t7848. If you compare the original and the newly read binary, you should be able to see which addresses have been written to successfully.

 

BTW, which games have you tried on the RAM cart that failed?

 

 

Ciao, Eckhard Stolberg

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only 8k. Damn

The first game I tried was Thrust but thats 16k. I also tried asteroids

and Kaboom.

 

Looks like I finaly found a use fo all those 486 motherboards in my garage :D

I just hope I can find a 32k chip ;)

 

Time to do some google searches, lest see .... MT5C6408-25 :ponder:

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Kaboom is a 2K game. You should use the -d command line option for those which will double up the ROM. Some 2K games were compiled for $f000-$f7ff, some were compiled for $f800-$ffff and some use both address ranges at the same time.

 

Most bankswitched games, like Thrust or Asteroids, don't work on the linear RAM cart. Graham has some designs for Atari's 2600 bankswitching style RAM carts that you could use for those.

 

You can write your own bankswitched games on the linear RAM cart though. You only need to put the different banks in the odd 4K parts of the RAM and design your bankswitching code to jump to the correct address when a switch is supposed to happen.

 

 

Ciao, Eckhard Stolberg

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