w83977eg Winbond Electronics Corp America, w83977eg Datasheet - Page 78

• Manufacturer Part Number: w83977eg
• Description: Winbond Isa I/o W83977ef W83977eg
• Manufacturer: Winbond Electronics Corp America

9.1
The Basic I/O functions of W83977EF/EG provide several I/O operations including driving a logic
value to output port, latching a logic value from input port, inverting the input/output logic value, and
steering Common Interrupt (only available in the second group of the GP I/O port). Common Interrupt
is the ORed function of all interrupt channels in the second group of the GP I/O ports, and it also
connects to a 1ms debounce filter which can reject a noise of 1 ms pulse width or less. There are two
8-bit registers (GP1 and GP2) which are directly connected to those GP I/O ports. Each GP I/O port is
represented as a bit in one of three 8-bit registers. Only 6 bits of GP2 are implemented. Table 7.1.1
shows their combinations of Basic I/O functions, and Table 7.1.2 shows the register bit assignments of
GP1 and GP2.
Table 9.1.1
0 = OUTPUT
1 = INPUT
I/O BIT
Basic I/O functions
0
0
0
0
1
1
1
1
ENABLE INT BIT
0 = DISABLE
1 = ENABLE
0
0
1
1
0
0
1
1
0 = NON INVERT
POLARITY BIT
1 = INVERT
W83977EF-AW/W83977EG-AW
0
1
0
1
0
1
0
1
-76-
Basic non-inverting output
Basic inverting output
Non-inverted output bit value of GP2
drive to Common Interrupt
Inverted output bit value of GP2 drive
to Common Interrupt
Basic non-inverting input
Basic inverting input
Non-inverted input drive to Common
Interrupt
Inverted input drive to Common
Interrupt
BASIC I/O OPERATIONS