W83977AF Information Storage Devices, Inc, W83977AF Datasheet - Page 123

• Manufacturer Part Number: W83977AF
• Description: W83877TF Plus Kbc, Cir, RTC
• Manufacturer: Information Storage Devices, Inc

W83977F/ W83977AF
PRELIMINARY
Figure 8.2
8.1
Basic I/O functions
The Basic I/O functions of W83977F/ AF 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 both groups of GP I/O ports.
Each GP I/O port is represented as a bit in one of two 8-bit registers. Only 6 bits of GP2 are
implemented. Table 11.1.1 shows their combinations of Basic I/O functions, and Table 11.1.2 shows
the register bit assignments of GP1 and GP2.
Publication Release Date: March 1998
-111 -
Revision 0.58