W83977ATF Datasheet, PDF (162/207 Pages) Winbond – WINBOND I/O

W83977ATF
PRELIMINARY
7.1 Basic I/O functions
The Basic I/O functions of W83977ATF 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 three 8-bit registers (GP1, GP2, and GP3) 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, GP2, and GP3.
Table 7.1.1
I/O BIT
0 = OUTPUT
1 = INPUT
0
0
0
0
1
1
1
1
ENABLE INT BIT
0 = DISABLE
1 = ENABLE
0
0
1
1
0
0
1
1
POLARITY BIT
0 = NON INVERT
1 = INVERT
0
1
0
1
0
1
0
1
BASIC I/O OPERATIONS
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
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Publication Release Date:April 1998
Revision 0.53