ZX Spectrum pinouts
From Petr Sladek
The original Sinclair ZX Spectrum Expansion Bus comes in several variants for different computers.
component side = A
solder side = B
ZX bus expansion pinout
The common ZX bus expansion pinout follows:
ZX bus expansion pinout differences
Different ZX Spectrum variants had slightly different bus expansion pinouts:
|pin||48K/+||128K/+2||2A, 2B and 3|
The Didaktik, the clone from the Czechoslovakia, had these differences:
AY sound chip
The AY-3-8910 is a 3-voice programmable sound generator (PSG) designed by General Instrument, also produced under license by Yamaha, later also under the Microchip Technology brand.
The same silicon chip was sold in three different packages: AY-3-8910, AY-3-8912, AY-3-8913.
The AY-3-8910 is a 40-pin package, it contains two general-purpose 8-bit parallel I/O ports A and B.
The AY-3-8912 is a 28-pin package, it contains one general-purpose 8-bit parallel I/O port A, while the other parallel port is simply not connected to any pins.
The 8912 was the most widely used variant.
The AY-3-8913 is a 24-pin package, with both parallel ports not connected.
register read: FFFD
data write: BFFD
data read: FFFD
tested address lines: A1, A14, A15
tested control signals: /WR, /RD, /IORQ
Warning: This collection is no more complete than informative!
Petr Sladek, the author of this ZX Spectrum pinouts collection,
reserves no warranty or
for informative purposes only,
do not build, modify nor enhance your devices
based on information found on this site,
you may seriously harm yourselves, your close ones,
your chips or your pets.