FDC37C669_07 SMSC [SMSC Corporation], FDC37C669_07 Datasheet - Page 26

• Manufacturer Part Number: FDC37C669_07
• Description: PC 98/99 Compliant Super I/O Floppy Disk Controller with Infrared Support
• Manufacturer: SMSC [SMSC Corporation]

Normal Floppy Mode
Normal mode. Register 3F3 contains only bits 0 and 1. When this register is read, bits 2 - 7 are a
high impedance.
Enhanced Floppy Mode 2 (OS2)
Register 3F3 for Enhanced Floppy Mode 2 operation.
For this mode, DRATE0 and DRATE1 pins are
inputs, and these inputs are gated into bits 6
and 7 of the 3F3 register. These two bits are
not affected by a hard or soft reset.
BIT 7 Reserved
BIT 6 Reserved
BITS 5 and 4 Drive Type ID - These Bits reflect
two of the bits of configuration register 6.
REG 3F3
REG 3F3 Reserved Reserved
Tri-state
DB7
DB7
Digital Output Register
Bit 1
0
0
1
1
Tri-state
DB6
DB6
Tri-state
Bit 0
0
1
0
1
DB5
DB5
Drive Type ID
Table 9 - Drive Type ID
Tri-state
DB4
DB4
26
CR6 - Bit 1
CR6 - Bit 3
CR6 - Bit 5
CR6 - Bit 7
Which two bits depends on the last drive
selected in the Digital Output Register (3F2).
(See Table 11)
BITS 3 and 2 Floppy Boot Drive - These bits
reflect the value of configuration register 7 bits
1, 0. Bit 3 = CR7 Bit DB1. Bit 2 = CR7 Bit DB0.
Bits
(READ/WRITE). Same as in Normal and
Enhanced Floppy Mode. 1.
Register 3F3 - Drive Type ID
Bit 5
Tri-state
Floppy Boot Drive
DB3
DB3
1
and
Tri-state
DB2
DB2
0
CR6 - Bit 0
CR6 - Bit 2
CR6 - Bit 4
CR6 - Bit 6
-
Bit 4
tape sel1 tape sel0
Tape
tape sel1 tape sel0
DB1
DB1
Drive
DB0
DB0
Select