W83877ATG Nuvoton Technology Corporation of America, W83877ATG Datasheet - Page 117

• Manufacturer Part Number: W83877ATG
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83877ATG

• Lead Free Status / RoHS Status: Supplier Unconfirmed

FDD A type 1, 0 (Bit 1, 0):
These two bits select the type of FDD A.
Three mode FDD select (EN3MODE = 1):
11.2.9 Configuration Register 8 (CR8), default = 00H
When the device is in Extended Function mode and EFIR is 08H, the CR8 register can be accessed
through EFDR. The bit definitions are as follows:
Bit 7 - bit 6: Reserved.
DISFDDWR (Bit 5):
This bit enables or disables FDD write data.
Once this bit is set high, the FDC operates normally, but because pin WE is inactive, the FDD will
not write data to diskettes. For example, if a diskette is formatted with DISFDDWR = 1, after the
format command has been executed, messages will be displayed that appear to indicate that the
format is complete. If the diskette is removed from the disk drive and inserted again, however, typing
the DIR command will reveal that the contents of the diskette have not been modified and the diskette
was not actually reformatted.
00
01
10
11
0
1
Selects normal mode. When RWC = 0, the data transfer rate is 250 Kb/s. When
Don't care RWC
Enables FDD write
Disables FDD write (forces pins WE , WD to stay high)
RWC = 1, the data transfer rate is 500 Kb/s.
RWC = 1, selects 1.44 MB high-density FDD.
RWC = 0, selects 1.2 MB high-density FDD.
7
6
,
selects 720 KB double-density FDD.
5
4
3
2
- 110 -
1
0
W83877ATF/W83877ATG
Floppy Boot Drive 0
Floppy Boot Drive 1
Media ID 0
Media ID 1
SWWP
DISFDDWR
reserved
reserved