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Drive Select

Keir Fraser edited this page Jan 17, 2020 · 9 revisions

[Greaseweazle F7 only]

Greaseweazle F7 supports Shugart and IBM/PC multi-drive setups.

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

A,B: IBM/PC

Two drives may be connected, each with an independent motor-enable line. The Greaseweazle connector acts the same as an IBM/PC motherboard: All PC drives are strapped for drive select on pin 12 (DS1) and motor select on pin 16, 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:

IBM/PC Cable

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.

F1 (Blue Pill) Limitations

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