Irem G-101 pinout
Irem G-101: 52-pin 0.6" high-density PDIP (canonically iNES Mapper 032)
.--\/--.
GND -- | 1 52| -- +5V
(f) M2 -> | 2 51| -> CIRAM A10 (f)
(f) R/W -> | 3 50| ??
(f) /ROMSEL -> | 4 49| -> PRG /CE (r)
(f) PPU A13 -> | 5 48| ??
(f) PPU RD# -> | 6 47| ??
(f) CPU A14 -> | 7 46| ??
(f) CPU A13 -> | 8 45| -> CHR /OE (r)
(fr) CPU A12 -> | 9 44| ??
(fr) CPU A2 -> |10 43| -> (always high)
(fr) CPU A1 -> |11 42| -> (always high)
(fr) CPU A0 -> |12 41| -> PRG A17 (r)
(f) PPU A12 -> |13 40| -> PRG A16 (r)
(f) PPU A11 -> |14 39| -> PRG A15 (r)
(f) PPU A10 -> |15 38| -> PRG A14 (r)
(fr) CPU D7 -> |16 37| -> PRG A13 (r)
(fr) CPU D6 -> |17 36| ??
(fr) CPU D5 -> |18 35| -> CHR A17 (f)
(fr) CPU D4 -> |19 34| -> CHR A16 (f)
(fr) CPU D3 -> |20 33| -> CHR A15 (f)
(fr) CPU D2 -> |21 32| -> CHR A14 (f)
(fr) CPU D1 -> |22 31| -> CHR A13 (f)
(fr) CPU D0 -> |23 30| -> CHR A12 (f)
? ?? |24 29| -> CHR A11 (f)
mode -> |25 28| -> CHR A10 (f)
GND -- |26 27| -- +5V
'------'
- mode tied to +5V: PRG banking mode selectable by software
- mode tied to gnd: PRG banking mode fixed to 8+8+16F (as in Major League)
- For the game Major League, CIRAM A10 is not connected to the G-101, and is instead simply tied to +5V
Reference: http://w.livedoor.jp/famicomcartridge/d/Irem%20G-101