ZX Spectrum Plus3 Expansion
Available at ZX Spectrum +3.
U 27 26 25 24 23 22 21 8 7 6 5 4 3 2 1
.-. .-. .-. .-. .-. .-. .-. .-. .-. .-. .-. .-. .-. .-. .-.
|^^^^^^^^^^^^^^^^^^^^^^^^^^^^ /////// ^^^^^^^^^^^^^^^|^^^^^^^^^^^^^^^^|
|____________________________ /////// _______________|________________|
`-' `-' `-' `-' `-' `-' `-' `-' `-' `-' `-' `-' `-' `-' `-'
L 27 26 25 24 23 22 21 8 7 6 5 4 3 2 1
EXPANSION I/O socket
| Pin | Upper row (U) | Lower row (L) |
|---|---|---|
| 1 | A15 | A14 |
| 2 | A13 | A12 |
| 3 | D7 | +5V |
| 4 | ROM 1 OE | not used |
| 5 | D0 | GND |
| 6 | D1 | GND |
| 7 | D2 | CK |
| 8 | D6 | A0 |
| 9 | D5 | A1 |
| 10 | D3 | A2 |
| 11 | D4 | A3 |
| 12 | INT | not used |
| 13 | NMI | GND |
| 14 | HALT | ROM 2 OE |
| 15 | MREQ | DISK RD |
| 16 | IORQ | DISK WR |
| 17 | RD | MOTOR ON |
| 18 | WR | BUSRQ |
| 19 | not used | RESET |
| 20 | WAIT | A7 |
| 21 | +12V | A6 |
| 22 | -12V | A5 |
| 23 | M1 | A4 |
| 24 | RFSH | not used |
| 25 | A8 | BUSACK |
| 26 | A10 | A9 |
| 27 | RESET | A11 |