Forums

Sega Master System / Mark III / Game Gear
SG-1000 / SC-3000 / SF-7000 / OMV
Home - Forums - Games - Scans - Maps - Cheats - Credits
Music - Videos - Development - Hacks - Translations - Homebrew

View topic - More PAL/NTSC timing issues

Reply to topic
Author Message
Michael Montague
  • Guest
Reply with quote
More PAL/NTSC timing issues
Post Posted: Thu Oct 21, 1999 9:07 am
Okay, I found my H-Scroll bug. Basically some games like 262 scanlines per V-Blank (my assumed NTSC) and some like 312 scanlines per V-Blank (my assumed PAL).

My question is: Can I tell from the ROM what country it was designed for? I know there are some check bits written in the ROM, but I seem to have lost the documentation for them.

Also, have the nationalization bits been better documented? I'd like to be able to tell games I'm either a Japan, US, or Europe system. Right now they all seem to think I'm a Mark III which can make some games hard to read. :)

- Mike
 
Nyef
  • Guest
Reply with quote
Post Posted: Thu Oct 21, 1999 2:47 pm
Quote
> Okay, I found my H-Scroll bug. Basically some games like 262 scanlines per V-Blank (my assumed NTSC) and some like 312 scanlines per V-Blank (my assumed PAL).

From what little info I have, this sounds like a good guess. Unfortunately, I only have info on black and white PAL systems (if that's not an oxymoron), so I can't tell how the number of cycles per scanline may have changed (if at all).

Quote
> My question is: Can I tell from the ROM what country it was designed for? I know there are some check bits written in the ROM, but I seem to have lost the documentation for them.

Even if there were some magic bit in the rom data block, don't rely on them. Always provide an override (and do as I say, not as I do).

Quote
> Also, have the nationalization bits been better documented? I'd like to be able to tell games I'm either a Japan, US, or Europe system. Right now they all seem to think I'm a Mark III which can make some games hard to read. :)

I'd like to know this as well. Zillion gets annoying in Japanese, as do some other games.

Quote
> - Mike

--Nyef
 
Michael Montague
  • Guest
Reply with quote
Post Posted: Fri Oct 22, 1999 12:44 am
Quote
> > Okay, I found my H-Scroll bug. Basically some games like 262 scanlines per V-Blank (my assumed NTSC) and some like 312 scanlines per V-Blank (my assumed PAL).

> From what little info I have, this sounds like a good guess. Unfortunately, I only have info on black and white PAL systems (if that's not an oxymoron), so I can't tell how the number of cycles per scanline may have changed (if at all).

Well, the numbers are easy to come up with. Since both PAL and NTSC are interlaced and the SMS refresh is not those two numbers are the number of scanlines on PAL and NTSC divided by half. (NTSC has 525 scalines, PAL 625). So it definatly makes sense why it works so well. :)

Quote
> > My question is: Can I tell from the ROM what country it was designed for? I know there are some check bits written in the ROM, but I seem to have lost the documentation for them.

> Even if there were some magic bit in the rom data block, don't rely on them. Always provide an override (and do as I say, not as I do).

Ah, yes, definatly want an override. Good idea.

Quote
> > Also, have the nationalization bits been better documented? I'd like to be able to tell games I'm either a Japan, US, or Europe system. Right now they all seem to think I'm a Mark III which can make some games hard to read. :)

> I'd like to know this as well. Zillion gets annoying in Japanese, as do some other games.

Hahaha, Zillion is my test case. :) I can read Katakana, but that font is HORRIBLE! I can just disassemble it and see what it is expecting. When I get around to that I'll post my results.

(I'm knee deep in sound code currently, ack!)

- Mike
 
Reply to topic



Back to the top of this page

Back to SMS Power!