INES Mapper 052: Difference between revisions
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* [http://nesdev.org/Mari7in1.txt "Mario Party" 7 in 1] by The Mad Dumper. | * [http://nesdev.org/Mari7in1.txt "Mario Party" 7 in 1] by The Mad Dumper. | ||
* [http://forums.nesdev.org/viewtopic.php?f=9&t=10703 Forum thread] about mapper 052 | * [http://forums.nesdev.org/viewtopic.php?f=9&t=10703 Forum thread] about mapper 052 by FARID | ||
Revision as of 09:56, 21 April 2015
iNES Mapper 052, like several other multicart mappers, supplements the MMC3's RAM with a single register for switching between unmodified MMC3-compatible games.
Registers:
---------------------------
$6000-7FFF: [WMCC SBPP] Multicart reg
P = PRG Block (bits 1,0)
= PRG A18 and A17
B = CHR+PRG Block Select bit (PRG and CHR bit 2)
= CHR and PRG A19
S = PRG Block size (0=256k 1=128k)
= 0=PRG A17 comes from MMC3 1=A17 comes from this register
C = CHR Block (bits 1,0)
= CHR A18 and A17
M = CHR Block size (0=256k 1=128k)
= 0=CHR A17 comes from MMC3 1=A17 comes from this register
W = 1=Disable multicart register and enable RAM
0=allow further writes to multicart register
$8000-FFFF: Same as MMC3 for selected block
This register can only be written to if PRG-RAM is enabled and writable (see $A001).
PRG Setup:
---------------------------
'S' PRG-AND PRG-OR
------------------------
0 $1F %BP0 0000
1 $0F %BPP 0000
'B' and 'P' bits make a 3-bit value used as PRG-OR (left shift 4). When 'S' is clear, the low bit of that
value is forced to 0.
PRG swapping behaves just like a normal MMC3 within this selected block
CHR Setup:
---------------------------
'M' CHR-AND CHR-OR
------------------------
0 $FF %BC 0000 0000
1 $7F %BC C000 0000
'B' and 'C' bits make a 3-bit value used as CHR-OR (left shift 7). When 'M' is clear, the low bit of
that value is forced to 0.
CHR swapping behaves just like a normal MMC3 within this selected block
Powerup and Reset:
---------------------------
$6000 set to 0 on reset and powerup.
The multicart register here can be implemented using two ICs: a 74273 (8 bit latch with asynchronous clear) and a 74153 (used as two independent one-of-two multiplexers). The 74273's /CLEAR input should be connected to something like
CPU M2 or CPU A0 --|>|--+-+-- /CLEAR
| |
R C
| |
gnd gnd
- Diode: 1N914 or any other small signal diode
- Resistor: approximately 10kΩ
- Capacitor: approximately 1nF
See also
- "Mario Party" 7 in 1 by The Mad Dumper.
- Forum thread about mapper 052 by FARID
