
W83977TF
PRELIMINARY
Publication Release Date: April 1998
-15 -
Revision 0.62
1.6 FDC Interface, continued
SYMBOL
PIN
I/O
FUNCTION
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).
1.7 KBC Interface
SYMBOL
PIN
I/O
FUNCTION
KDATA
59
I/OD
16u
I/OD
16u
I/OD
16u
I/OD
16u
I/O
12t
I/O
12t
Keyboard Data
MDATA
60
PS2 Mouse Data
KCLK
67
Keyboard Clock
MCLK
68
PS2 Mouse Clock
GA20
GP11
(IRQIN2)
56
KBC GATE A20 (P21) Output. (CR2A bit 6 = 0, default)
General purpose I/O port 1 bit 1. (CR2A bit 6 = 1)
Alternate Function from GP11: Interrupt channel input.
KBRST
GP12
(WDTO)
57
I/O
12t
I/O
12t
W83C45 Keyboard Reset (P20) Output. (CR2A bit 7 = 0, default)
General purpose I/O port 1 bit 2. (CR2A bit 7 = 1)
Alternate Function 1 from GP12 : Watchdog timer output.