Sunsoft 5 pinout

Sunsoft FME-7 (and Sunsoft 5B): 44-pin TQFP

                           / \
                          / O \
         (nrw) CPU D3 -> /01 44\ <- CPU D2 (nrw)
                 varies /02   43\ <- CPU D4 (nrw)
             varies <- /03     42\ <- CPU D1 (nrw)
            (n) M2 -> /04       41\ <- CPU D5 (nrw)
      (n) CPU A13 -> /05         40\ <- CPU D0 (nrw)
             GND -- /06           39\ -- +5V
    (n) CPU A14 -> /07             38\ <- CPU D6 (nrw)
   (n) /ROMSEL -> /08               37\ <- CPU D7 (nrw)
(nrw) CPU R/W -> /09                 36\ -> PRG A13 (r)
    (n) /IRQ <- /10                   35\ -> PRG A16 (r)
(n) PPU /RD -> /11                     34\ -> PRG A14 (r)
(n) PPU A10 -> \12                     33/ -> PRG A15 (r)
 (n) PPU A11 -> \13                   32/ -> PRG A17 (r)
  (n) PPU A12 -> \14                 31/ -> PRG /CE (r)
   (n) PPU A13 -> \15               30/ -> PRG RAM /CE (w)
    (r) CHR /CE <- \16             29/ -> PRG RAM +CE (w)
             +5V -- \17           28/ -- GND
                  ?? \18         27/ varies
(nr) CHR/CIRAM A10 <- \19       26/ -> CHR A17 (r)
        (r) CHR A16 <- \20     25/ -> CHR A15 (r)
         (r) CHR A11 <- \21   24/ -> CHR A14 (r)
          (r) CHR A13 <- \22 23/ -> CHR A12 (r)
                          \   /
                           \ /
pin 2: Amplifier in (5B) or ?PRG A18 out (FME-7)?
pin 3: Amplifier out (5B)
pin 18: Audio /disable (5B) [1] - has internal pullup
pin 27: Audio out (5B) or +5V (FME-7)

n: connects to NES (CPU or PPU)
r: connects to ROM (PRG or CHR)
w: connects to WRAM

Expansion audio mixing circuit:[2]
                                     +                 +
           From S5B----/\/\/---+---||---+---/\/\/---+---||---To RF
           (S5B.27)    1K      |   1u   |   100K    |   1u   (Cart.46)
                               |        |           |
           From 2A03---/\/\/---+        |           |
           (Cart.45)   10K              |           |
                                        |           |
           Amp. In----------------------+           |
           (S5B.2)                                  |
                                                    |
           Amp. Out---------------------------------+
           (S5B.3)

On FME-7, the two ground supplies and three +5V supplies are shorted internally. Boards (like GRM-E301) that were used with the 5A or 5B did not connect pin 27 to +5V.

On FME-7, pin 3 has an overvoltage protection diode only; pin 18 has both over- and under- voltage protection diodes. Functionality is still not known.