VRC3 pinout

VRC3: 18-pin PDIP (iNES Mapper 073)

r: connects to PRG ROM
f: connects to Famicom
w: connects to PRG RAM
                 .-\_/-.
  (r) PRG A16 <- |01 18| -- +5V
  (r) PRG /CE <- |02 17| -> WRAM /CE (w)
  (r) PRG A14 <- |03 16| <- CPU RnW (wfr)
  (r) PRG A15 <- |04 15| <- CPU D3 (wfr)
   (f) CPU M2 -> |05 14| <- CPU D0 (wfr)
(wfr) CPU A12 -> |06 13| <- CPU D1 (wfr)
 (rf) CPU A13 -> |07 12| <- CPU D2 (wfr)
  (f) CPU A14 -> |08 11| <- nROMSEL (f)
          Gnd -- |09 10| -> nIRQ
                 '-----'