FDC37M81x SMSC Corporation, FDC37M81x Datasheet - Page 22

• Manufacturer Part Number: FDC37M81x
• Description: PC98/99 Compliant Enhanced Super I/O Controller
• Manufacturer: 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.
REG 3F3
REG 3F3 Reserved Reserved
Note:
Tri-state
DIGITAL OUTPUT REGISTER
DB7
DB7
L0-CRF2-Bx = Logical Device 0, Configuration Register F2, Bit x.
Bit 1
0
0
1
1
Tri-state
DB6
DB6
Bit 0
Tri-state
0
1
0
1
DB5
DB5
Drive Type ID
Table 7 - Drive Type ID
Tri-state
DB4
DB4
22
L0-CRF2 - B1
L0-CRF2 - B3
L0-CRF2 - B5
L0-CRF2 - B7
REGISTER 3F3 - DRIVE TYPE ID
Bit 5
Tri-state
Floppy Boot Drive
DB3
DB3
Tri-state
DB2
DB2
L0-CRF2 - B0
L0-CRF2 - B2
L0-CRF2 - B4
L0-CRF2 - B6
Bit 4
tape sel1
tape sel1
DB1
DB1
tape sel0
tape sel0
DB0
DB0