W83977ATF Datasheet, PDF (164/207 Pages) Winbond – WINBOND I/O

W83977ATF
PRELIMINARY
7.2 Alternate I/O Functions
W83977ATF provides several alternate functions which are scattered among the GP I/O ports. Table
7.2.1 shows their assignments. Polarity bit can also be set to alter their polarity.
Table 7.2.1
GP I/O PORT
GP10
GP11
GP12
GP13
GP14
GP15
GP16
GP17
GP20
GP21
GP22
GP23
GP24
GP25
GP30
GP31
GP32
GP33
GP34
ALTERNATE FUNCTION
Interrupt Steering
Interrupt Steering
Watch Dog Timer Output/IRRX input
Power LED output/IRTX output
General Purpose Address Decoder/Keyboard Inhibit(P17)
General Purpose Write Strobe/ 8042 P12
Watch Dog Timer Output
Power LED output
Keyboard Reset (8042 P20)
8042 P13
8042 P14
8042 P15
8042 P16
GATE A20 (8042 P21)
Interrupt Steering
Interrupt Steering
General Purpose Address Decoder
General Purpose Address Decoder
Watch Dog Timer Output
7.2.1 Interrupt Steering
GP10, GP11, GP30, and GP31 can be programmed to map their own interrupt channels. The
selection of IRQ channel can be done in configuration registers CR70 and CR72 of logical device 7
and logical device 9. Each interrupt channel also has its own 1 ms debounce filter that is used to
reject any noise whose width is equal to or less than 1 ms.
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Publication Release Date:April 1998
Revision 0.53