Western Digital FD1771

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Western Digital datasheet for the FD1771 floppy disk controller FD1771 FDC Datasheet.jpg
Western Digital datasheet for the FD1771 floppy disk controller

The FD1771, sometimes WD1771, is a floppy disk controller chip, the first in a line of floppy disk controllers produced by Western Digital. It uses single density FM encoding introduced in the IBM 3740. Later models in the series added support for MFM encoding and increasingly added onboard circuitry that formerly had to be implemented in external components. Originally packaged as 40-pin dual in-line package (DIP) format, [1] [2] later models moved to a 28-pin format that further lowered implementation costs.

Contents

Derivatives

The FD1771 was succeeded by many derivatives that were mostly software-compatible:

Compatible chips

FD1771 on a Cromemco 4FDC S-100 board. FD1771 is directly below the word Cromemco at the top of the board. Cromemco 4FDC color adjusted.jpg
FD1771 on a Cromemco 4FDC S-100 board. FD1771 is directly below the word Cromemco at the top of the board.

Many compatible chips were available from other vendors:

These were used in many microcomputers including the TRS-80, Acorn Electron, BBC Master, Atari ST, Acorn Archimedes, and the SAM Coupé, as well as the +D and DISCiPLE disk interfaces for the ZX Spectrum, the Commodore 157x/1581 for the Commodore 64 and the Atari XF551 for the Atari 8-bit computers.

References

  1. Michalopoulos, Demetrios A (October 1976). "New Products: Single-chip floppy disk formatter/controller". Computer. 9 (10). IEEE: 64. doi:10.1109/C-M.1976.218414."The FD1771 is a single-chip floppy disk formatter/controller that interfaces with most available disk drives and virtually all types of computers."
  2. "Recent IC Announcements". Computer. 9 (10). IEEE: 66. October 1976. doi:10.1109/C-M.1976.218417. The FD1771 was announced on July 19, 1976, and sold for $60 each in lots of 100.
  3. Guzis, Charles P. (2009-09-13). "Durango GCR". Sydex. Archived from the original on 2017-03-25. Retrieved 2017-03-25.
  4. "Recent IC Announcements". Computer. 10 (12). IEEE: 140. December 1977. doi:10.1109/C-M.1977.217618. The FD1781 was announced on September 21, 1977. Supported Dual density; accommodates MFM, M2FM.
  5. "Dual Density Floppy Controller Chip". Byte. 3 (3): 216. March 1978.
  6. FD 179X-02 datasheet
  7. WD279X-02 datasheet
  8. WD177X-00 datasheet images

Further reading