Basic rom replacement revisited

[redman]

Hello all,

 

I just finished putting a 27C801 eprom into an 800XL to replace the Basic rom. The eprom holds 128 8K images. I put in just about every 8K image that I could find knowing that some of them wouldn't work. About 80 of them work. Some of them were probably for the 2600 and some may need conversion. I'll post a list soon with the names of games that worked and also those that didn't. I mounted 7 switches on the top right of the computer for rom selection. It turned out to be a good project because my grand niece can't get enough of Pacman & Frogger.

 

Redman

[Rybags]

I doubt that games like Star Raiders that operate as "Diagnostic" carts will work in that way.

 

They rely on the OS giving them control immediately, so won't necessarily work if the OS has partially initialized.

 

Just checked part of the Reset routine... it uses TRIG3 to detect the cart, which is problem #1.

 

Problem #2 is that early in the powerup stage, BASIC is disabled anyway... I believe that the arse-about way of switching ROMs ie-0 to enable BASIC but 0 to disable the other ROM parts is likely due to the powerup default of $FF in the PIA outputs.

 

You could do a bit of creative hacking and get the cart images to run properly. The OS Manual describes the cold/warmstart processes and lists the cart locations and vectors you need to look at.

[Fres]

Good luck converting the 2600 ones, though.

[redman]

Good luck converting the 2600 ones, though.

 

That's not what I meant. I don't think anyone is trying to convert 2600 dumps. I knew some of them were probably 2600 images and wouldn't work because of that. Others wouldn't work, like Star Raiders & River Raid, because they needed to be converted or modified because of the "Diagnostic cart" problem. I used the converted Star Raiders & River Raid images that I got here at AtariAge and they work perfectly. I just used 128 8K images that I had and I feel very lucky that about 80 of them worked.

[redman]

Hello all,

 

I just finished putting a 27C801 eprom into an 800XL to replace the Basic rom. The eprom holds 128 8K images. I put in just about every 8K image that I could find knowing that some of them wouldn't work. About 80 of them work. Some of them were probably for the 2600 and some may need conversion. I'll post a list soon with the names of games that worked and also those that didn't. I mounted 7 switches on the top right of the computer for rom selection. It turned out to be a good project because my grand niece can't get enough of Pacman & Frogger.

 

Redman

 

Here's the list of stuff that worked and didn't work.

atariage.txt

[Rybags]

Don't take this as gospel, but here's my opinion on a few...

 

9 Asteroids runs as a diag

12 Basketball possibly diag, also most likely a 4K cartridge

16 Buck Rogers - could it be a banked cart?

13 Battlezone - banked cart?

45 Ghostbusters - if it's same as the Activision disk game, then definately a banked cart

52 Jungle Hunt - 16K cart

66 Mario Bros - 16K

 

Actually - a pattern emerges. I'd say that a good deal of these games just don't work because they're 16K carts, and I'm guessing you have this EPROM setup as 8K?

 

A possible solution would be to rework the thing, but would involve some heavy work. If the bank selection could be driven by software rather than a hard switch you could just setup a menu system.

For the 16K and larger games, rather than running from the ROM, you'd need to copy them to RAM, switch out the ROM then run them.

Of course in that instance, you'd need cracked images as most of the originals would self-destruct the RAM code.

[Nukey Shay]

No 2600 titles would work (of course), so you should check your roms with Good2600 to see if any of those files are 2600 binaries. Many of the ones you listed show identical filenames to the ones used for Atari 2600 titles in 8.3 format.

Goodtools would pick them out for you. The same would go for 7800 and 5200 binaries...get 'em out of your archive before you burn a chip.

 

As far as sizes go, a directory on your computer would show which ones are not 8k. I don't understand why you should doubt it and burn them to the multicart chip anyway :-/

[Urchlay]

One quick & dirty way to tell if a cart is diagnostic: if it runs in the Atari800 emulator without you having the OS ROM, it's a diag. For sure Basketball and Star Raiders will work this way in Atari800 2.0.3.

 

Not sure whether this applies to the WinPlus version of the emulator or not.

[redman]

Hello,

I'm redoing an old project that replaces the Basic rom in an 800XL with a 27c801 eprom. It's very hard to find 128 8K cart images that work. I've run into a few problems.

Carts that don't work that I would love to have fixed versions of:

known diagnostic carts - Asteroids and Basketball
Keystone Kapers, Twin Pack - Sinker+Teaser not sure why they don't work
K-Razy Kritters, K-Star Patrol, Pool400, Monster Maze and Gorf - they need osb

 

If you know of fixed versions please let know.
Thanks a lot.

Redman