w83977ctf Winbond Electronics Corp America, w83977ctf Datasheet - Page 105

• Manufacturer Part Number: w83977ctf
• Description: Winbond I/o
• 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
= 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
= 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.
setting pin is NRTSA (pin 43).
on selecting IRQ
effective on selecting IRQ
selecting IRQ
on selecting IRQ
IRQ
selecting IRQ
IRQ
selecting IRQ
-96 -
Publication Release Date: March 1999
W83977EF/ CTF
PRELIMINARY
Revision A1