
W83977EF/ CTF
PRELIMINARY
Publication Release Date: March 1999
-17 -
Revision A1
1.6 FDC Interface, continued
SYMBOL
PIN
I/O
FUNCTION
DSA#
14
OD
24
Drive Select A. When set to 0, this pin enables disk drive A.
This is an open drain output.
DSB#
15
OD
24
Drive Select B. When set to 0, this pin enables disk drive B.
This is an open drain output.
MOA#
16
OD
24
Motor A On. When set to 0, this pin enables disk drive 0. This is
an open drain output.
DSKCHG#
4
IN
cs
Diskette change. This signal is active low at power on and
whenever the diskette is removed. This input pin is pulled up
internally by a 1 K
resistor. The resistor can be disabled by bit
7 of L0-CRF0 (FIPURDWN).
RDATA#
6
IN
cs
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).
WP#
7
IN
cs
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).
TRAK0#
8
IN
cs
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).
INDEX#
17
IN
cs
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).