W83977F Datasheet, PDF (152/181 Pages) Winbond – PLUG & PLAY 1.0A COMPLIANT

W83977F/ W83977AF
CREC (GP24, Default 0x01)
PRELIMINARY
Bit 7-5 : Reserved.
Bit 4-3 : Select Function.
= 00 Select Basic I/O function
= 01 Reserved
= 10 Select 2nd alternate function : Keyboard P16 I/O
= 11 Reserved
Bit 2 : Int En
= 1 Enable Common IRQ
= 0 Disable Common IRQ
Bit 1 : Polarity : 1 : Invert, 0 : No Invert
Bit 0 : In/Out : 1 : Input, 0 : Output
CRED (GP25, Default 0x01)
Bit 7-4 : Reserved.
Bit 3 : Select Function.
= 1 Select alternate function: GATE A20(Connect to KBC P21).
= 0 Select basic I/O function
Bit 2 : Int En
= 1 Enable Common IRQ
= 0 Disable Common IRQ
Bit 1 : Polarity : 1 : Invert, 0 : No Invert
Bit 0 : In/Out : 1 : Input, 0 : Output
CRF0 (Default 0x00)
Debounce Filter Enable or Disable for General Purpose I/O Combined Interrupt. The Debounce Filter
can reject a pulse with 1ms width or less.
Bit 7-4 : Reserved
Bit 3 : GP Common IRQ Filter Select
= 1 Debounce Filter Enabled
= 0 Debounce Filter Bypassed
Bit 2-0 : Reserved
CRF1 (Reserved)
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Publication Release Date: March 1998
Revision 0.58