BU3266 / BU3270 pinout
Custom Nintendo PIO chip found in the New Famicom (HVC-101). This replaces the U3 (139) and the U7/U8 (368).
.---v---.
INV 3I -> |01 32| -- +5V
INV 3O <- |02 31| -> INV 3B1
M2 -> |03 30| -> INV 3B2
A15 -> |04 29| -> /ROMSEL
A14 -> |05 28| -> PPU /CE
A13 -> |06 27| -> CPU RAM /CE
P1 D0 -> |07 26| <- INV 2I
P0 D0 -> |08 25| -> INV 2O
P1 D1 -> |09 24| -> CPU D0
P0 D1 -> |10 23| -> CPU D1
P1 D2 -> |11 22| <- /INP0 ($4016 /RD)
P0 D2 -> |12 21| <- /INP1 ($4017 /RD)
P1 D3 -> |13 20| -> CPU D2
P1 D4 -> |14 19| -> CPU D3
GND -- |15 18| -> CPU D4
INV 1I -> |16 17| -> INV 1O
'-------'
Notes:
- INV 1I/O (16-17) = Audio Inverter
- INV 2I/O (25-26) = PA13 Inverter
- INV 3I/O/B1/B1 (01,02,30,31) = unused (intended for CIC clock based on topology) [1]
Sources: