Caltron 6 in 1

Cartridge Front

Cartridge Board, Front

Box, Cart Sleeve, and Manual

What Is It?

The Caltron 6 in 1. Supposidly "legit", but I dunno. Some of the games have shown up on other multicarts.

The Games:

Cosmos Cop
Magic Carpet 1001
Balloon Monster
Adam & Eve

The Tech:

Lots of weird crap, as the usual for these carts. There's a bunch of stuff on there related solely for lockout defeat. There is basically 3 different defeater circuits on there, and the switch lets you select which to use. I guess they figure if they can find 3 marginal hacks, one will have to work on your NES. :-)

Mapper operation:

OK, this is one sadistic mapper circuit.

There are two registers on it... I will call them Reg1 and Reg2 for
simplicity sake.

When the NES is switched on, or the reset button is pressed, both
registers are cleared to 00h.  There is a cool little diode / RC circuit
on the M2 line that does this.


Reg1 is the "main control" register.  It has six bits.

You write to it by writing a byte to 06000h thru 067ffh.  Like other
multicarts, the address lines are used instead of the datalines, and the
value of the byte written has no effect.  A0 = bit 0, A1 = bit 1, etc.

A0-A5 are used:


0 - PRG 0
1 - PRG 1
2 - PRG 2 / enable second register * (see text)
3 - CHR 2
4 - CHR 3
5 - Mirror control.  0 = V, 1 = H

PRG 0-2 specify a 32K PRG bank that appears at 8000-FFFF.  Note that the
banks are 32K in size, and there are 8 of them for a total PRG size of
256K bytes.

Bit 2 is strange.  When it is 1, it enables writes to the second register.


Reg2 is the "auxilary CHR control" register.  It only has 2 bits.

You write to it at 08000-0ffffh.  Writes are only accepted if bit 2 of
reg1 is set.  Writes are rejected if this bit is 0!  Unlike the above
register, writes this one relies on what is written instead of the address
it is written to.


0 - CHR 0
1 - CHR 1

CHR bits 0,1 (from this register) and bits CHR bits 2,3 (from reg1) select
the desired bank for the CHR ROM.  There are 16 8K banks for a total of
128K bytes worth of CHR ROM

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