
W83637HF
Publication Release Date: June 25, 2003
- 11 -
Revision 1.3
5.2 FDC Interface
SYMBOL
DRVDEN0
PIN
1
I/O
OD
24t
IN
csu
FUNCTION
Drive Density Select bit 0.
INDEX#
3
This Schmitt-triggered 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 a 1 K
resistor. The resistor can be disabled by bit 7 of L0-CRF0
(FIPURDWN).
Motor A On. When set to 0, this pin enables disk drive 0. This is
an open drain output.
Drive Select B. When set to 0, this pin enables disk drive B.
This is an open drain output.
0V to +5V amplitude fan tachometer input
MOA#
4
OD
24t
DSB#
FANIN3
DSA#
5
OD
24t
I/O
24ts
OD
24t
6
Drive Select A. When set to 0, this pin enables disk drive A.
This is an open drain output.
Motor B On. When set to 0, this pin enables disk drive 1. This is
an open drain output.
Fan speed control. Use the Pulse Width Modulation (
PWM
)
technical knowledge to control the Fan's RPM.
Direction of the head step motor. An open drain output.
Logic 1 = outward motion
Logic 0 = inward motion
Step output pulses. This active low open drain output produces a
pulse to move the head to another track.
Write data. This logic low open drain writes pre-compensation
serial data to the selected FDD. An open drain output.
Write enable. An open drain output.
MOB#
FANPWM3
7
OD
24t
OD
24t
DIR#
8
OD
24t
STEP#
9
OD
24t
WD#
10
OD
24t
WE#
TRACK0#
11
OD
24t
IN
csu
13
Track 0. This Schmitt-triggered 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 a 1 K
resistor. The resistor
can be disabled by bit 7 of L0-CRF0 (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 a 1 K
resistor. The resistor can be
disabled by bit 7 of L0-CRF0 (FIPURDWN).
The read data input signal from the FDD. This input pin is pulled
up internally by a 1 K
resistor. The resistor can be disabled by
bit 7 of L0-CRF0 (FIPURDWN).
Head select. This open drain output determines which disk drive
head is active.
Logic 1 = side 0
Logic 0 = side 1
WP#
14
IN
csu
RDATA#
15
IN
csu
HEAD#
16
OD
24t