W83877TF Datasheet, PDF(24/154 Page) Winbond – I/O chip disk drive adapter

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W83877TF Datasheet, PDF (24/154 Pages) Winbond – I/O chip disk drive adapter

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W83877TF

1.4 FDC Interface

SYMBOL PIN

DIR

HEAD

RWC

STEP

INDEX

TRAK0

RDATA

DSKCHG

I/O

OD24

INcs

FUNCTION

Write enable. An open drain output.

Direction of the head step motor. An open drain output.

Logic 1 = outward motion

Logic 0 = inward motion

Head select. This open drain output determines which disk drive

head is active.

Logic 1 = side 0

Logic 0 = side 1

Reduced write current. This signal can be used on two-speed

disk drives to select the transfer rate. An open drain output.

Logic 0 = 250 Kb/s

Logic 1 = 500 Kb/s

When bit 5 of CR9 (EN3MODE) is set to high, the three-mode

FDD function is enabled, and the pin will have a different

definition. Refer to the EN3MODE bit in CR9.

Write data. This logic low open drain writes precompensation

serial data to the selected FDD. An open drain output.

Step output pulses. This active low open drain output produces a

pulse to move the head to another track.

This schmitt input from the disk drive is active low when the

head is positioned over the beginning of a track marked by an

index hole. This input pin is pulled up internally by an

approximately 1K ohm resistor. The resistor can be disabled by

bit 4 of CR6 (FIPURDWN).

Track 0. This schmitt input from the disk drive is active low when

the head is positioned over the outermost track. This input pin is

pulled up internally by an approximately 1K ohm resistor. The

resistor can be disabled by bit 4 of CR6 (FIPURDWN).

Write protected. This active low schmitt input from the disk drive

indicates that the diskette is write-protected. This input pin is

pulled up internally by an approximately 1K ohm resistor. The

resistor can be disabled by bit 4 of CR6 (FIPURDWN).

The read data input signal from the FDD. This input pin is pulled

up internally by an approximately 1K ohm resistor. The resistor

can be disabled by bit 4 of CR6 (FIPURDWN).

Diskette change. This signal is active low at power on and

whenever the diskette is removed. This input pin is pulled up

internally by an approximately 1K ohm resistor. The resistor can

be disabled by bit 4 of CR6 (FIPURDWN).

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Publication Release Date: March 1998

Version 0.61

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