W83977F-A Datasheet, PDF (130/182 Pages) Winbond – WINBOND I/O

W83977F-A/ W83977G-A/ W83977AF-A/ W83977AG-A
Bit 5 : URBTRI
Bit 4 : URATRI
Bit 3 : PRTTRI
Bit 2 : IRTRI [W83977AF only]
Bit 1 : Reserved.
Bit 0 : FDCTRI.
CR26 (Default 0b0s000000)
Bit 7 : SEL4FDD
= 0 Select two FDD mode.
= 1 Select four FDD mode.
Bit 6 : HEFRAS
These two bits define how to enable Configuration mode.
HEFRAS Address and Value
= 0 Write 87h to the location 3F0h twice.
= 1 Write 87h to the location 370h twice.
Bit 5 : LOCKREG
= 0 Enable R/W Configuration Registers.
= 1 Disable R/W Configuration Registers.
Bit 4 : DSIRLGRQ [W83977AF only]
= 0 Enable IR legacy mode on IRQ and DRQ selection, then MCR register bit 3 is effective
in selecting IRQ and DRQ.
= 1 Disable IR legacy mode on IRQ and DRQ selection, then MCR register bit 3 is not
effective in selecting IRQ and DRQ.
Bit 3 : DSFDLGRQ
= 0 Enable FDC legacy mode on IRQ and DRQ selection, then DO register bit 3 is effective
in selecting IRQ
= 1 Disable FDC legacy mode on IRQ and DRQ selection, then DO register bit 3 is not
effective in selecting IRQ
Bit 2 : DSPRLGRQ
= 0 Enable PRT legacy mode on IRQ and DRQ selection, then DCR bit 4 is effective on
selecting IRQ
= 1 Disable PRT legacy mode on IRQ and DRQ selection, then DCR bit 4 is not effective
on selecting IRQ
Bit 1 : DSUALGRQ
= 0 Enable UART A legacy mode IRQ selecting, then MCR bit 3 is effective on selecting
IRQ
= 1 Disable UART A legacy mode IRQ selecting, then MCR bit 3 is not effective on
selecting IRQ
Bit 0 : DSUBLGRQ
= 0 Enable UART B legacy mode IRQ selecting, then MCR bit 3 is effective on selecting
IRQ
= 1 Disable UART B legacy mode IRQ selecting, then MCR bit 3 is not effective on
selecting IRQ
CR28 (Default 0x00)
Bit 7-5: Reserved.
Bit 4 : IRQ Sharing selection.
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