Browse Prior Art Database

STEP and DIRECTION Control Circuit for Disc Drive

IP.com Disclosure Number: IPCOM000047331D
Original Publication Date: 1983-Nov-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Derdall, BC: AUTHOR

Abstract

A logic circuit for the step/direction drive control of a stepping motor comprises a pair of flip-flops. cross-coupled to form a four-step ring counter. Referring to the figure, the direction of the stepper drive is determined by the phase of ACCESS 0 and ACCESS 1 drive lines. The flip-flops FF1 and FF2 are initialized through the POWER ON RESET, and then each pulse on the STEP line will switch one of the flip-flops. With a "high" signal on the DIRECTION line, flip-flop FF2 data input is gated from FF1-Q and FF1 data from FF2-Q. In this mode, ACCESS 0 will lag ACCESS 1 by 90Πand cause the access head of the disc drive to step in the "out" direction with each pulse applied to the STEP line. With a "low" signal on the DIRECTION line, FF1 data input is gated from FF2-Q while FF2 data input is gated from FF1-Q.

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STEP and DIRECTION Control Circuit for Disc Drive

A logic circuit for the step/direction drive control of a stepping motor comprises a pair of flip-flops. cross-coupled to form a four-step ring counter. Referring to the figure, the direction of the stepper drive is determined by the phase of ACCESS 0 and ACCESS 1 drive lines. The flip-flops FF1 and FF2 are initialized through the POWER ON RESET, and then each pulse on the STEP line will switch one of the flip-flops. With a "high" signal on the DIRECTION line, flip-flop FF2 data input is gated from FF1-Q and FF1 data from FF2-Q. In this mode, ACCESS 0 will lag ACCESS 1 by 90OE and cause the access head of the disc drive to step in the "out" direction with each pulse applied to the STEP line. With a "low" signal on the DIRECTION line, FF1 data input is gated from FF2-Q while FF2 data input is gated from FF1-Q. In this mode ACCESS 0 will lead ACCESS 1 by 90OE causing the access head to step in the "in" direction with each pulse applied to the STEP line. If TRACK 0 goes "high" along with DIRECTION, inverted AND gate A1 is enabled, thus disabling AND gate A2 and preventing any further movement of the access head in the "out" direction. A typical application of this circuit is in the control of a floppy disc drive by a commercial controller chip.

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