w83977eg Winbond Electronics Corp America, w83977eg Datasheet - Page 88

• Manufacturer Part Number: w83977eg
• Description: Winbond Isa I/o W83977ef W83977eg
• Manufacturer: Winbond Electronics Corp America

CR26 (Default 0b0s000000)
Bit 7: SEL4FDD
Bit 6: HEFRAS
HEFRAS Address and Value
Bit 5: LOCKREG
Bit 4: Reserved.
Bit 3: DSFDLGRQ
Bit 2: DSPRLGRQ
Bit 1: DSUALGRQ
Bit 0: DSUBLGRQ
= 0
= 1
These two bits define how to enable Configuration mode. The corresponding power-on
setting pin is NRTSA (pin 43).
= 0 Write 87h to the location 3F0h twice.
= 1 Write 87h to the location 370h twice.
= 0 Enable R/W Configuration Registers.
= 1 Disable R/W Configuration Registers.
= 0 Enable FDC legacy mode on IRQ and DRQ selection, then DO register bit 3 is effective
= 1 Disable FDC legacy mode on IRQ and DRQ selection, then DO register bit 3 is not
effective on selecting IRQ
= 0 Enable PRT legacy mode on IRQ and DRQ selection, then DCR bit 4 is effective on
= 1 Disable PRT legacy mode on IRQ and DRQ selection, then DCR bit 4 is not effective
= 0 Enable UART A legacy mode IRQ selecting, then MCR bit 3 is effective on selecting
= 1 Disable UART A legacy mode IRQ selecting, then MCR bit 3 is not effective on
= 0 Enable UART B legacy mode IRQ selecting, then MCR bit 3 is effective on selecting
= 1 Disable UART B legacy mode IRQ selecting, then MCR bit 3 is not effective on
Select two FDD mode.
Select four FDD mode.
on selecting IRQ
selecting IRQ
on selecting IRQ
IRQ
selecting IRQ
IRQ
selecting IRQ
W83977EF-AW/W83977EG-AW
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