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Country code method

1: Which method do you prefer?

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Mega Drive header: country codes

#1 User is offline Sik 

Posted 04 February 2008 - 10:53 AM

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As you know, normally the country code is set in $1F0 in three bytes. In those three bytes you have to specify the following letters, one for each region, and leave unused bytes as spaces:
  • J: Japan
  • U: America
  • E: Europe
However, in the Technicall Bulletin #31, Sega suggests a new method for country codes. In this method one byte is always used. You must make a four bit value based on the allowed regions, and put it at $1F0 as a hexadecimal value in ASCII (watch out with that, don't put the value straight as it is).
  • Bit 0: Domestic, NTSC (Japan)
  • Bit 1: Domestic, PAL (Invalid?)
  • Bit 2: Overseas, NTSC (America)
  • Bit 3: Overseas, PAL (Europe)
The point is, which method do you prefer? The old one or the new one? Yes, this is a poll. Just to see if we want to change our standard for setting that or not. I plan to implement checking for both method in the 2gen BIOS (if I continue working on it :)), by the way. You choose.

#2 User is offline drx 

Posted 04 February 2008 - 11:28 AM

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You sure you haven't mixed it with $a10001?

In any case, the first one is better.

#3 User is offline Sik 

Posted 04 February 2008 - 01:00 PM

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Yes, I'm sure. There are two bits in $A10001, while there are four in these specs I'm talking about.

Genesis Technical Bulletin #31 said:

1. Changes to cartridge data (ID) specifications
Please note that the specifications below also apply to Genesis 32X.

The following changes have been made to the code entered in 1F0h.
  • Old: Country code data
  • New: 1 byte ASCII hardware enable code in 1F0h.
    1F1h to 1FFh are filled with the "space" character code (20h).
  • Explanation
    The hardware enable code is used when the application reads the hardware data information in
    $A10001 in order to perform territory lockout. The code is used by SEGA to check hardware and
    software compatibility.
 $A10001					  Main sales		Hardware Enable Code (numbers from 0 to F below)
Bit7 Bit6 Hardware type	   territories	   0 1 2 3 4 5 6 7 8 9 A B C D E F

  0   0	Japan, NTSC	Japan,S.Korea,Taiwan  X O X O X O X O X O X O X O X O
  0   1	Japan, PAL						   X X O O X X O O X X O O X X O O
  1   0   Overseas, NTSC  N.America,Brazil	  X X X X O O O O X X X X O O O O
  1   1   Overseas, PAL   Europe,Hong Kong	  X X X X X X X X O O O O O O O O

Ex. 1) The hardware enable code "F" is entered in applications that do not limit hardware compatibility
(I.e., a universal compatibility ROM). As can be seen in the table above, the hardware enable
code "F" is compatible with all hardware types.

Ex. 2) For applications that are compatible only with the US version of the Genesis, the hardware
enable code "4" is used. The application is compatible only with hardware that shows Bit 7 = 1
and Bit 6 = 0 at $A10001.


#4 User is offline drx 

Posted 04 February 2008 - 03:26 PM

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Ah, yes, I remember that!

It's an interesting concept, but... JUE is my preference (visibility, ease of use).

#5 User is offline Sik 

Posted 04 February 2008 - 08:27 PM

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The main problem with it is that it's written in ASCII. If it was a straight value, a simple btst would do. Also, '4', '8', 'B', 'E' and 'F' are used in the old system (them all work as the same, just 'J', 'U', 0 (PAL Jap) and 'W' (all regions become valid) don't), and conflict with the new one, again because it's ASCII. So bad. But the new one looks cool in some sense :P

Anyways, I gave a null vote because I wanted to know your opinion, not mine :P
This post has been edited by Sik the Hedgehog: 04 February 2008 - 08:28 PM

#6 User is offline Tweaker 

Posted 04 February 2008 - 09:09 PM

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The new method is MUCH more optimized, and a lot simpler to work with. I'm voting for that one.

#7 User is offline TmEE 

Posted 04 April 2008 - 01:43 AM

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I use old method... usually "EUJ and Estonia " string... plain ASCII, nothing more or less. The program doesn't even care what's written

#8 User is offline Uberham 

Posted 14 May 2008 - 12:35 PM

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AFAIK, DOMESTIC PAL refers to Korea, as they have both PAL AND NTSC TV's so it'd make sense to have what GENS calls "Japanese PAL"
This post has been edited by Uberham: 14 May 2008 - 12:35 PM

#9 User is offline Nemesis 

Posted 20 May 2008 - 12:26 AM

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Technically, the second one is the better system. That said, I prefer the first.

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