INES Mapper 132 is used to denote three compatible boards used by games from TXC Corporation:
| Title | Cartridge code | PRG-ROM | CHR-ROM | Notes |
|---|---|---|---|---|
| 棋王 (Qíwáng, Chinese Chess) | MGC-001 | 64 KiB | 32 KiB | |
| Creatom | MGC-003 | 64 KiB | 32 KiB | |
| 小瑪琍 (Xiǎo Mǎlí) | MGC-005 | 16 KiB | 8 KiB | TXC re-release, no bankswitching or copy-protection. Cartridge label titles it Bingo. |
| 麻将方块 (Mahjong Block) | MGC-008 | 32 KiB | 32 KiB | TXC re-release |
| Venice Beach Volley | MGC-010 | 32 KiB | 32 KiB | TXC re-release |
| Rad Racket - Deluxe Tennis II | MGC-011 | 32 KiB | 32 KiB | TXC re-release |
Its UNIF board name is UNL-22211.
Mapper 132 uses a custom IC (real number 05-00002-010, often with fake markings) serving as a latch, adder and inverter. There are six registers: "P", "R", and Output (three bits each); "S", inCrement, and and inVert (one bit each).
Mask: $E100
read $4100: [xxxx SRRR]
|||| ||||
|||| ++++- Copy internal registers 'RRR' and 'S' XOR 'V' to data bus.
++++------ open bus
Mask: $E103
write $4100: If Increment is set, internal register 'RRR' <- 'RRR'+1
Otherwise, if Invert is clear, copy internal register 'PPP' to 'RRR'
if Invert is set, copy '~PPP' to 'RRR'
'S' is not changed at all.
write $4101: [.... ...V] - Invert Mode
write $4102: [.... SPPP] - Copy data bus to internal registers 'S' and 'PPP'.
'S' can be read back immediately; 'PPP' must be copied using $4100 first.
write $4103: [.... ...C] - Increment Mode
Mask: $8000
write $8000: copy internal register 'RRR' to PRG A15, CHR A14, and CHR A13 banking pins, in order.
Games will also check the lower three or four bits of $4100 for the correct value after several increment and inversion operations as a copy-protection measure.
Instead of the 05-00002-010 ASIC, the 01-22270-000 PCB variant can also use a simple 74LS161 latch, which would make the board function as MHROM.