There have been a lot of people asking when this will go on sale so we will release for sale the bare version right now! This version is just the adapter. It does not have a cart shell or box but it can fit in an OG shell if a slot is cut out of the top. Some time in the future we will release a version with a cart shell and a Collectors version. Prices below:
(Now Available!) Regular version with cart shell/label --- $49
(Now Available!) Collectors version --- $59
Shipping in USA is flat Priority for $10. International is actual cost.
Bare bones MarkMaster --- $39 --- (Discontinued)
IF YOU ARE NOT A MEMBER HERE YOU CAN ORDER BY SENDING AN EMAIL TO 'my username with _ instead of -' at hotmail dot com
MarkMaster: SG-1000/SC-3000/Mark III to (western) Master System adapter (no BIOS mod)
1) Why is it even needed?
First SG-1000/SC-3000/Mark III have a different cartridge connector (2x44p, 0.125" pitch) than western Master Systems consoles (2x50p, 0.1" pitch). Pinout is of course also different.
Secondly, western Master System consoles embed a BIOS doing several checks on the cartridge ROM header on boot up. None of the SG-1000 games are compliant and many of the Mark III ones aren't either.
2) But there's already similar adapters you can use on a Megadrive/Genesis with a Power Base Converter.
Yes, that's because the Megadrive/Genesis in Master System mode has no BIOS, hence no header checks.
3) What are those header checks?
- presence of the string "TMR SEGA" at offset 7ff0, 3ff0 or 1ff0
- region code (defined by the upper nibble of the 16th byte in the header) must be equal to 4 (= SMS export)
- checksum calculation: add all bytes in the cartridge ROM but the header to produce a two byte value (carry is dropped over and over). Range on which the calculation is made is provided by the lowest nibble of the 16th byte in the header.
4) Wouldn't using a completely passive adapter then replacing the BIOS by a Japanese one (or disabling it) achieve the same thing?
That's right but:
- not everyone wants to modify their consoles
- not everyone has the right tools and skills (though not terribly difficult) to do it
- the mod would be tied to the console
5) What about compatibility? Are there any incompatible games?
I'd say compatibility should be 95%+ (possibly even higher).
(Now Available!) Regular version with cart shell/label --- $49
(Now Available!) Collectors version --- $59
Shipping in USA is flat Priority for $10. International is actual cost.
IF YOU ARE NOT A MEMBER HERE YOU CAN ORDER BY SENDING AN EMAIL TO 'my username with _ instead of -' at hotmail dot com
MarkMaster: SG-1000/SC-3000/Mark III to (western) Master System adapter (no BIOS mod)
1) Why is it even needed?
First SG-1000/SC-3000/Mark III have a different cartridge connector (2x44p, 0.125" pitch) than western Master Systems consoles (2x50p, 0.1" pitch). Pinout is of course also different.
Secondly, western Master System consoles embed a BIOS doing several checks on the cartridge ROM header on boot up. None of the SG-1000 games are compliant and many of the Mark III ones aren't either.
2) But there's already similar adapters you can use on a Megadrive/Genesis with a Power Base Converter.
Yes, that's because the Megadrive/Genesis in Master System mode has no BIOS, hence no header checks.
3) What are those header checks?
- presence of the string "TMR SEGA" at offset 7ff0, 3ff0 or 1ff0
- region code (defined by the upper nibble of the 16th byte in the header) must be equal to 4 (= SMS export)
- checksum calculation: add all bytes in the cartridge ROM but the header to produce a two byte value (carry is dropped over and over). Range on which the calculation is made is provided by the lowest nibble of the 16th byte in the header.
4) Wouldn't using a completely passive adapter then replacing the BIOS by a Japanese one (or disabling it) achieve the same thing?
That's right but:
- not everyone wants to modify their consoles
- not everyone has the right tools and skills (though not terribly difficult) to do it
- the mod would be tied to the console
5) What about compatibility? Are there any incompatible games?
I'd say compatibility should be 95%+ (possibly even higher).
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... and I thought I was a sega fan boy !
