Jump to content
IGNORED

OS with Asteroids help!


SoundGammon

Recommended Posts

The Asteroids BIOS is universal and was designed to work in either PAL or NTSC 7800s. Apparently Atari was planning on shipping it in NTSC 7800s at one point but it never happened. There is a prototype ROM of the Asteroids BIOS that is NTSC only.

 

Mitch

  • Like 3
Link to comment
Share on other sites

The prototype ROM of the Asteroids BIOS that is NTSC only is included as part of the bulk BIOS archive for the A7800 emulator. It is the file

"c300558-001a.u7" highlighted below:

 

attachicon.gifA7800BIOS.PNG

Looks like you are missing the Pole Position BIOS, the proto NTSC BIOS and the alternate highscore ROM.

 

Mitch

  • Like 1
Link to comment
Share on other sites

*does searches, looks at pictures of installation instructions...

I may attempt this, but my 7800 board looks NOTHING like the pictures I've seen, especially the one above.

Then what does your 7800 board look like?! Because all the NTSC boards basically look the same layout wise. Only the extra timing stuff on the right middle changes as those are either populated or not in some cases.

Link to comment
Share on other sites

Looks like you are missing the Pole Position BIOS, the proto NTSC BIOS and the alternate highscore ROM.

 

Mitch

 

Sorry, I didn't mean to imply the "bulk" BIOS archive for the A7800 emulator is all-inclusive.

I believe the folder capture below covers the additional BIOS files you mentioned and some others.

I think it has all the HSC ROM files also, or there might be a third one not in the folder.

A couple of other files may be 'scattered' elsewhere too. I might have to snoop around in my folders and files.

 

post-18-0-90146000-1556495574.png

 

*Edit: Looking over that list, I spelled Asteroids incorrectly, or was that intentional.

:ponder:

*Edit2: Nope...just a typo on my part. :-D

Link to comment
Share on other sites

I think I've seen these boards before with the Goldstar ram chips in them but never really looked that closely. I do know I've seen them where that main ground rail in the middle cuts off at that cap at C22 instead of running further down the board. I guess since I've only ever had to focus on the video section of these, I've never noticed the extra jumpers etc. It is also doesn't have the silkscreen for the rarely installed 2nd 3904 tranny under the crystal that usually has a resistor shoved in there instead.

Link to comment
Share on other sites

If I'm reading that board right it looks like it could handle a 28 pin SRAM on the bottom socket closest to the BIOS. I'm gonna guess that is what the other jumpers are for. Maybe W4 is the equal to W1 on the other board? I can't see all the traces to see if that goes to the high address on the 24 or 28 pin BIOS chip to know for sure.

Link to comment
Share on other sites

Here's a close up of the section I was talking about. Notice the 'W3', 'W4', 'W5, & 'W6' jumpers left & above the color wheel.

attachicon.gif20190428_220000.jpg

 

Haven't seen a picture with this one in it...

 

Interesting how many variants there are for such an "unsuccessful" system, eh? My second 7800 (and daily player) is an A1 serial number machine with an Expansion Port that has a similar layout, but not at all identical.

 

post-30400-0-79135500-1556577545_thumb.jpg

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...