[Homebrew Code Examples]

Amazing! Mine will arrive soon :-) 7800 there we go!

[6502 Instruction Set Guide - printed booklet]

Hah, got mine already but I have to say it looks simply gorgeous in that way. I may order it too.

[6502 Instruction Set Guide - printed booklet]

That would also be nice.

[6502 Instruction Set Guide - printed booklet]

One of each three, to be more precise...

[6502 Instruction Set Guide - printed booklet]

This is sad. I went to his site from time to time. 

 

Just writing to let you know I purchased one book. Thank you very much.

[Atari 7800 color format]

Oh, ok. Good to know Thankyou.

[Atari 7800 color format]

Are the base rgb values documented?

[Atari 7800 color format]

Thankyou for your help Are the bright values 0000 or 1111 only? Or are intermediate values allowed?

[Atari 7800 color format]

Thanks, i'll try to disassemble it

[Atari 7800 color format]

What i want to say, is: does the 7800 have a fixed color palette? Like "color 1 is black, color 2 is red" etc, a color number that's later retrieved by the vdp from palette ram to paint the color in the tv (i bet that's not the way, because there isn't any place in the memory map) or a 8 bit value composed with a few bits for the color, like (for example!) 3 bits for red, 3 for green and 2 for blue? Any help would be very appreciated!

[Atari 7800 color format]

I see in the Maria register list this info:

 

0020 - Background color

0021 - Palette 0 color 1

0022 - Palette 0 color 2

0023 - Palette 0 color 3

0025 - Palette 1 color 1

0026 - Palette 1 color 2

0027 - Palette 1 color 3

 

(etc)

 

What values do i have to store in those registers? I mean, what color format does the 7800 use? If i want a blue or a red, how do i specify it? Thanks

[Calling all Atari 7800 programmers]

I'm enlisted now too

[New digital signature generator]

MorphOS would be interesting

[Atari 7800 bios source code]

Hello Bruce, thanks a lot for this, i'll take a look inmediatmently

[Atari 7800 bios source code]

Thanks a lot Mitch It does have two different bytes with the one i had Weird! The source code i have is the one here at atari age. I'll look into the pdf at the web you pointed me

[Atari 7800 bios source code]

Sorry for always asking about programming stuff guys

I'm reading the 7800 bios disassembly and i'm surprised about this:

 

STA LF112

 

LF112 label is not defined in any place of the code or am i becoming crazy of reading too much 6502 asm lately? Did anyone tried to assemble again this file?

[Another question between Pal and NTSC games :)]

Funny I was asking because i have read somewhere that a pal game on a ntsc console can display a rolling image because being out of sync.

[Another question between Pal and NTSC games :)]

Hi, i'm curious about those PAL<->NTSC conversions, what are the differences? Doesn't the video chips handle all the TV stuff, or an Atari 7800 game needs to access at "low level" to the TV? Or maybe it's just to change a byte somewhere to init the video hardware in a different way?

[Disassembling 7800 games]

Oh, Bruce thanks I was forgetting the reset vector, now all looks better Thanks a lot to all of you guys

[Disassembling 7800 games]

Mmm are you sure? As far as i know, 7800 games have a checksum check, like some other consoles, to ensure the game is licensed, but nothing more

[Disassembling 7800 games]

Hello guys I have another question to you. After downloading some Atari 7800 games i noticed something that i don't understand. First bytes of the roms (raw .bin dumps, or after the 128 bytes of the A78 header) there are bytes that can't be 6502 code. For example, Xenophobe NTSC contains a lot of AA bytes, Asteroids NTSC a repeating pattern 03 FC 00, or Ace of Aces, that even contains a lot of ascii code! What i'm missing here? I tought the game code started in the first byte of the rom!

 

Thaaaaanks a lot for your help

[Cosmetical differences between PAL and NTSC games]

Oh, by the way, what gold sticker?

[Cosmetical differences between PAL and NTSC games]

It's good to know, i'll have to put in different place pal and ntsc games so i don't mix them.... Thanks

[Cosmetical differences between PAL and NTSC games]

So i can't difference between an unopened PAL and unopened NTSC game? Wops

[Cosmetical differences between PAL and NTSC games]

Hi, i'm just curious about the differences between the PAL and the NTSC releases of the Atari 7800 games. There's any difference in manuals, boxes, and cartridge labels?