FDC37C669-MS Standard Microsystems (SMSC), FDC37C669-MS Datasheet - Page 31

• Manufacturer Part Number: FDC37C669-MS
• Manufacturer: Standard Microsystems (SMSC)

Specifications of FDC37C669-MS

• Pin Count: 100
• Lead Free Status / RoHS Status: Compliant

DIGITAL INPUT REGISTER (DIR)
Address 3F7 READ ONLY
This register is read-only in all modes.
PC-AT Mode
BIT 0 - 6 UNDEFINED
The data bus outputs D0 - 6 will remain in a high
impedance state during a read of this register.
PS/2 Mode
BIT 0 nHIGH DENS
This bit is low whenever the 500 Kbps or 1 Mbps data
rates are selected, and high when 250 Kbps and 300
Kbps are selected.
BITS 1 - 2 DATA RATE SELECT
These bits control the data rate of the floppy controller.
See Table 13 for the settings corresponding to the
individual data rates. The data rate select bits are
unaffected
RESET
RESET
COND.
COND.
CHG
DSK
CHG
N/A
DSK
N/A
7
7
by
N/A
N/A
6
1
6
N/A
N/A
5
1
5
N/A
N/A
4
1
4
a
31
N/A
N/A
3
1
3
BIT 7 DSKCHG
This bit monitors the pin of the same name and reflects
the opposite value seen on the disk cable.
software reset, and are set to 250 Kbps after a hardware
reset.
BITS 3 - 6 UNDEFINED
Always read as a logic "1"
BIT 7 DSKCHG
This bit monitors the pin of the same name and reflects
the opposite value seen on the disk cable.
DRATE
SEL1
N/A
N/A
2
2
DRATE
SEL0
N/A
N/A
1
1
DENS
HIGH
N/A
0
1
0