SP0256 Pin-Outs

 1 GND
 2 /RESET
 3 ROM DISABLE
 4 C1
 5 C2
 6 C3
 7 VCC1
 8 SBY
 9 /LRQ
 10 A8
 11 A7
 12 SER OUT
 13 A6
 14 A5
 15 A4
 16 A3
 17 A2
 18 A1
 19 SE
 20 /ALD
 21 SER IN
 22 TEST
 23 VCC2
 24 PWM OUT
 25 /SBY RESET
 26 ROM CLK
 27 OSC1
 28 OSC2

The oscillator should be 3.12MHz Allows to output sounds up to 5kHz (ie. the output is updated at 10kHz rate). The SP0256 is reportedly expandable to "491 K of ROM" (probably bullshit). The SP0256B is reportedly expandable to "480 K of ROM" (probably K=Kbits). The TEST pin of the SP0256 chip can be used (among others) to dump its internal ROM. Note: Details on TEST are found in the "SP0256B" datasheet - but not in the "SP0256" datasheet - not sure if the pin works identical for both chip types, nor if there's a difference between them at all.

 1 GND
 2 C3
 3 NC
 4 ROM CLK
 5..6 NC
 7 CS1
 8 /CS2
 9 /ROM ENABLE
 10 SERIAL OUT
 11 VCC
 12..13 NC
 14 SERIAL IN
 15 C1
 16 C2

 1 GND
 2 C3
 3 NC
 4 ROM CLK
 5..10 NC
 11 CS1
 12 /CS2
 13 /ROM ENABLE
 14 SERIAL OUT
 15 VCC
 16..21 NC
 22 SERIAL IN
 23 C1
 24 C2