Browse Prior Art Database

Full Media Support for Diskette Drives without Media Sensing

IP.com Disclosure Number: IPCOM000113324D
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Combs, JL: AUTHOR

Abstract

Disclosed is the addition of an external Programmable Array Logic* (PAL) circuit modifying the operation of the Western Digital diskette drive controller WD37C65 so that all four media formats are supported. This PAL circuit PAL16V8 can be added to the normal logic of the controller without cutting any traces or wires.

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Full Media Support for Diskette Drives without Media Sensing

      Disclosed is the addition of an external Programmable Array
Logic* (PAL) circuit modifying the operation of the Western Digital
diskette drive controller WD37C65 so that all four media formats are
supported.  This PAL circuit PAL16V8 can be added to the normal logic
of the controller without cutting any traces or wires.

      Fig. 1 is a table showing how bits are used to determine the
mode of the diskette.  The CR1 and CR0 bits are controlled by
software, and the DRV bit is externally fixed high or low.  The
addition of the PAL circuit forces the RPM bit to a zero state when
the CR1 bit is at a one state, allowing the use of drives without
media sensing.

      Fig. 2 is a schematic diagram showing connections between the
diskette drive controller WD37C65 and the PAL circuit PAL16V8.

*  Trademark of Advanced Micro Devices Corporation.