
W83977F/ W83977AF
PRELIMINARY
Publication Release Date: March 1998
-17 -
Revision 0.58
1.6 FDC Interface, continued
SYMBOL
PIN
17
I/O
IN
cs
FUNCTION
INDEX
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, which
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
OUT
12t
I/O
12t
Keyboard Data
MDATA
60
PS2 Mouse Data
KCLK
67
Keyboard Clock
MCLK
68
PS2 Mouse Clock
GA20
GP11
(IRQIN2)
56
CR2A bit6= 0 (default): Keyboard GATE A20 (P21) Output.
CR2A bit6= 1: General purpose I/O port 1, bit 1. It can be
configured as an interrupt channel.
KBRST
GP12
(WDTO,
IRRX)
57
OUT
12t
I/O
12t
CR2A bit7= 0 (default): Keyboard Reset (P20) Output.
CR2A bit7= 1: General purpose I/O port 1, bit 2. It can be
configured as watchdog timer output or IRRX (SINC if UART C is
used as a simple serial port
[W83977AF only]
) input.
KBLOCK
GP13
(PLEDO,
IRTX)
58
IN
16tu
I/O
16tu
CR2B bit0= 0 (default): Keyboard KINH (P17) Input.
CR2B bit0= 1: General purpose I/O port 1, bit 3. It can be
configured as watchdog timer output or IRTX (SOUTC if UART C
is used as a simple serial port
[W83977AF only]
) output.
1.8 RTC Interface
SYMBOL
PIN
I/O
FUNCTION
VBAT
64
RTC battery voltage input
XTAL1
63
IN
C
O
8t
RTC 32.768Khz Clock Input
XTAL2
61
RTC 32.768Khz Clock Output
1.9 POWER PINS
VCC
20,55,
85,115
+5V power supply for the digital circuitry
GND
25,62,
90,120
Ground