w83977ctf Winbond Electronics Corp America, w83977ctf Datasheet - Page 95

• Manufacturer Part Number: w83977ctf
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

7.1
The Basic I/O functions of W83977EF/CTF 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 GP I/O ports). Common Interrupt is
the ORed function of all interrupt channels in the second group of 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 these 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 7.1.1
0 = OUTPUT
1 = INPUT
I/O BIT
0
0
0
0
1
1
1
1
Basic I/O functions
ENABLE INT BIT
0 = DISABLE
1 = ENABLE
0
0
1
1
0
0
1
1
0 = NON INVERT
POLARITY BIT
1 = INVERT
-86 -
0
1
0
1
0
1
0
1
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
Publication Release Date: March 1999
BASIC I/O OPERATIONS
W83977EF/ CTF
PRELIMINARY
Revision A1