Drive Select

Greaseweazle supports Shugart and IBM/PC multi-drive setups¹.

The read and write commands both accept option --drive N where N is one of A, B, 0, 1, or 2. Note that N is not case sensitive: a and b are also accepted.

The default is A (IBM/PC Drive A) requiring an IBM/PC drive and a "cable with a twist" (see the explanation below). If your drive fails with a Track 0 not found error, you may have:

• A Shugart drive, strapped for DS0 (pin 10): Connect with straight ribbon and use --drive 0
• A PC drive being used with a straight cable: Use --drive b

Note: Greaseweazle F1 does not support multiple drives and any specified non-default drive letter will be ignored.

A,B: IBM/PC

In IBM/PC mode the Greaseweazle header acts the same as on a PC motherboard: Two drives may be connected, each with an independent motor-enable line. All PC drives are strapped for drive-select DS1 (pin 12), and a cable twist is used to differentiate between drives A and B:

• A: Drive connected via a cable with twist on pins 10-16
• B: Drive connected via a straight ribbon cable

A two-drive cable will have connector(s) before and after a twist, as shown.

0,1,2: Shugart

Up to three drives may be connected, with drive-select lines DS0-DS1 on pins 10, 12 and 14 respectively. All drives share a common motor-select signal on pin 16. Drives are addressed by drive identifiers 0, 1, and 2.

Summary

The diagrams below summarise the use of pins 10-16 on the respective buses. Click for full-size.

1. Except Greaseweazle F1 (basic Blue Pill model).