Macintosh Floppy Drive Connector
This document details the connectors used by Macintosh computers to connect internal and external floppy drives.
The information here is provided on a best-effort basis and is not guaranteed to be accurate. Use at your own risk.
Connector Diagrams
2x10 Pin Header
``` Male:
| 2 4 6 8 10 12 14 16 18 20 |
| 1 3 5 7 9 11 13 15 17 19 |
-------------- --------------
```
19-Pin D-Subminiature Connector
``` Male:
\ 1 2 3 4 5 6 7 8 9 10 / \ 11 12 13 14 15 16 17 18 19 /
```
The non-standard 19-pin D-subminiature connector used for external drive connectors is frequently referred to as a "DB-19", but this is incorrect as "DB" refers to a larger D-subminiature shell size which holds 25, 44, or 52 (typically 25) pins.
Pin Assignments (Common)
| Pin Name/Function | Source | Direction | D-Subminiature Pin | 2x10 Header Pin | | --------------------- | ------------ | --------- | ------------------ | --------------- | | Ground | Power Supply | -- | 1, 2, 3, 4* | 1, 3, 5, 7 | | § (see below) | | | 5 | 9 | | +5V | Power Supply | -> | 6 | 11 | | +12V | Power Supply | -> | 7, 8 | 13, 15, 17, 19 | | ¶ (see below) | | | 10 | 20 | | CA0 / Phase0 | IWM/SWIM | -> | 11 | 2 | | CA1 / Phase1 | IWM/SWIM | -> | 12 | 4 | | CA2 / Phase2 | IWM/SWIM | -> | 13 | 6 | | CA3 / Phase3 / LSTRB | IWM/SWIM | -> | 14 | 8 | | !WRREQ / Write Enable | IWM/SWIM | -> | 15 | 10 | | SEL / Head Select | VIA | -> | 16 | 12 | | !ENBL / Drive Enable | IWM/SWIM | -> | 17 | 14 | | RD / Read | IWM/SWIM | <- | 18 | 16 | | WR / Write | IWM/SWIM | -> | 19 | 18 |
* The last ground (D-subminiature pin 4) is left floating by drives compatible with Apple II computers.
Direction is Macintosh relative to drive.
Pin Assignments (Per Drive)
§
| Drive | Pin Name/Function | Direction | | ---------------------------------- | ----------------- | --------- | | 400K Disk Drive | -12V | -> | | 800K Disk Drive with Black Label | Not Connected | -- | | 800K Disk Drive with Red Label | !EJECT | -> | | Automatic-Inject SuperDrive (FDHD) | !EJECT | -> |
Direction is Macintosh relative to drive.
¶
| Drive | Pin Name/Function | Direction | | ---------------------------------- | ----------------- | --------- | | 400K Disk Drive | PWM | -> | | 800K Disk Drive with Black Label | Not Connected | -- | | 800K Disk Drive with Red Label | !CSTOUT | <- | | Automatic-Inject SuperDrive (FDHD) | !CSTOUT | <- |
Direction is Macintosh relative to drive.
Pin Assignments (Per Macintosh Model)
§
| Macintosh Model | Pin Name/Function | Source | Direction | | ----------------------- | ----------------- | ------------ | --------- | | 128K, 512K, 512Ke, Plus | -12V | Power Supply | -> | | SE, IIcx, IIci* | -12V | Power Supply | -> | | Other | Not Connected | -- | -- |
* D-subminiature connector only; on 2x10 pin header, this pin is not connected.
Direction is Macintosh relative to drive.
¶
| Macintosh Model | Pin Name/Function | Source | Direction | | ----------------------- | --------------------------- | ------------ | --------- | | 128K, 512K, 512Ke, Plus | PWM | ASG PAL | -> | | SE* | PWM | BBU | -> | | IIcx, IIci | PWMPU (+5V pullup resistor) | Power Supply | -> | | SE FDHD, SE/30 | +5V | Power Supply | -> | | Other† | Not Connected | -- | -- |
* D-subminiature connector only; on 2x10 pin header, this pin is not connected.
† Macintosh models with manual-inject floppy drives may connect this pin to ground, which may cause automatic-inject floppy drives to eject constantly.
Direction is Macintosh relative to drive.