34 PIN FEMALE EDGE at the computer.
The Amstrad CPC6128 (1985) provides a Centronics-compatible parallel printer interface via a 34-pin PCB edge connector, using the 36-pin Centronics numbering convention with pins 18 and 36 absent on the physical connector. The interface carries TTL-level signals and uses a /STROBE–BUSY handshake, as in the Centronics standard, but only seven data bits (D0–D6) are available to software; D7 is permanently wired to ground on the standard CPC. The CPC+ variant introduced a 25-pin D-type female connector with full 8-bit data output.
| Pin | Name | Description |
|---|---|---|
| 1 | /STROBE | Strobe |
| 2 | D0 | Data 0 |
| 3 | D1 | Data 1 |
| 4 | D2 | Data 2 |
| 5 | D3 | Data 3 |
| 6 | D4 | Data 4 |
| 7 | D5 | Data 5 |
| 8 | D6 | Data 6 |
| 9 | GND | Ground |
| 10 | n/c | Not connected |
| 11 | BUSY | Busy |
| 12 | n/c | Not connected |
| 13 | n/c | Not connected |
| 14 | GND | Ground |
| 15 | n/c | Not connected |
| 16 | n/c | Not connected |
| 17 | n/c | Not connected |
| 16 | GND | Ground |
| 17 | n/c | Not connected |
| 19 | GND | Ground |
| 20 | GND | Ground |
| 21 | GND | Ground |
| 22 | GND | Ground |
| 23 | GND | Ground |
| 24 | GND | Ground |
| 25 | GND | Ground |
| 26 | GND | Ground |
| 27 | n/c | Not connected |
| 28 | GND | Ground |
| 29 | n/c | Not connected |
| 30 | n/c | Not connected |
| 31 | n/c | Not connected |
| 32 | n/c | Not connected |
| 33 | GND | Ground |
| 34 | n/c | Not connected |
| 35 | n/c | Not connected |
Notes
- Pin 18 does not exist on the physical 34-pin edge connector; the numbering follows the 36-pin Centronics convention with pins 18 and 36 omitted.
- D7 is tied to GND on the standard CPC6128; effective data width is 7 bits (D0–D6) only.
- /STROBE is hardware-inverted by the CPC circuit: writing bit 7 = 0 to the I/O port produces /STROBE = 1 (inactive); writing bit 7 = 1 produces /STROBE = 0 (active).
- BUSY is an input, readable as bit 6 of PPI port B.
- The port is accessed via an I/O write with address line A12 = 0; bits 0–6 carry D0–D6, bit 7 controls /STROBE.
- The CPC+ uses a 25-pin D-type female connector and adds D7 output, making it an 8-bit port.
Signals
- /STROBE — active-low output; pulses low to signal that valid data is present on D0–D6; hardware-inverted from the I/O port bit.
- D0–D6 — parallel data output lines (TTL level); 7-bit effective data width on the standard CPC6128.
- BUSY — input from the printer; high while the printer is processing data; the host must wait for BUSY to deassert before sending the next byte.
- GND — signal ground; multiple pins provide return paths for data and control lines.