W83977AF Information Storage Devices, Inc, W83977AF Datasheet - Page 27

• Manufacturer Part Number: W83977AF
• Description: W83877TF Plus Kbc, Cir, RTC
• Manufacturer: Information Storage Devices, Inc

1.6 FDC Interface
DRVDEN0
DRVDEN1
GP10
(IRQIN1)
P12
DSRC
HEAD
DIR
MOB
DSA
DSB
MOA
DSKCHG
RDATA
WE
WD
STEP
WP
TRAK0
SYMBOL
PIN
10
11
12
13
14
15
16
2
3
5
9
4
6
7
8
OD
OD
OD
OD
OD
OD
OD
OD
OD
OD
OD
IN
IN
IN
IN
I/O
cs
cs
cs
cs
24
24
24
24
24
24
24
24
24
24
24
Drive Density Select bit 0.
Drive Density Select bit 1.
Alternate Function 1: General purpose I/O port 1, bit 0. It can be
configured as an interrupt channel.
Alternate Function 2: Keyboard P12 I/O port.
Alternate Function 3: DSR input of UART C [W83977AF only]
Head select. This open drain output determines which disk drive
head is active.
Logic 1 = side 0; Logic 0 = side 1
Write enable. An open drain output.
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.
Direction of the head step motor. An open drain output.
Logic 1 = outward motion; Logic 0 = inward motion
Motor B On. When set to 0, this pin enables disk drive 1. This is an
open drain output.
Drive Select A. When set to 0, this pin enables disk drive A. 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.
Motor A On. When set to 0, this pin enables disk drive 0. This is an
open drain output.
Diskette change. This signal is active low at power on and when the
diskette is removed. This input pin is pulled up internally by a 1 K
resistor, which can 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
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
CRF0 (FIPURDWN).
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
7 of L0-CRF0 (FIPURDWN).
resistor, which can be disabled by bit 7 of L0-
resistor, which can be disabled by bit 7 of L0-
FUNCTION
W83977F/ W83977AF
resistor, which can be disabled by bit
Publication Release Date: March 1998
-16-
PRELIMINARY
Revision 0.58