CR1F
of this register after power up is 00H. This register
indicates the Drive Type used for each drive. Refer to
CR0B for Data Rate Table register.
This register can only be accessed in the Configuration
Mode and after the CSR has been initialized
1FH. The default value
to
FDD3
FDD2
FDD1
FDD0
D7
D6
D5
D4
D3
D2
D1
D0
DT0
DT1
DT0
DT1
DT0
DT1
DT0
DT1
DTx = Drive Type select
DRVDEN0
(Note)
DRVDEN1
(Note)
DT0
DT1
Drive Type
0
0
DENSEL
DRATE0
4/2/1 MB 3.5"
2/1 MB 5.25" FDDS
2/1.6/1 MB 3.5" (3-MODE)
0
1
1
1
0
1
DRATE1
nDENSEL
DRATE0
DRATE0
DRATE0
DRATE1
PS/2
Note:
DENSEL, DRATE1 and DRATE0 map onto two output pins DRVDEN0 and DRVDEN1.
be set to 48 locations, on 16 byte boundaries from
CR20
This register can only be accessed in the Configuration
Mode and after the CSR has been initialized to 20H.
The default value of this register after power up is 3CH.
This register is used to select the base address of the
floppy disk controller (FDC). The FDC can
100H-3F0H. To disable the FDC, set ADR9 and ADR8
to zero.
Upper Address Decode requirements: nCS='0' and
A10='0' are required to access the FDC registers. A[3:0]
are decoded as 0XXXb.
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
ADR9
ADR8
ADR7
ADR6
ADR5
ADR4
0
0
131
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