Advanced I/O Controller with Motherboard GLUE Logic
Datasheet
6.4.6 TAPE DRIVE REGISTER (TDR)
Address 3F3 READ/WRITE
The Tape Drive Register (TDR) is included for 82077 software compatibility and allows the user to assign
tape support to a particular drive during initialization. Any future references to that drive automatically
invokes tape support. The TDR Tape Select bits TDR.[1:0] determine the tape drive number. Table 6.5
illustrates the Tape Select Bit encoding. Note that drive 0 is the boot device and cannot be assigned tape
support. The remaining Tape Drive Register bits TDR.[7:2] are tristated when read. The TDR is
unaffected by a software reset.
Table 6.5 - Tape Select Bits
TAPE SEL1
(TDR.1)
TAPE SEL0
(TDR.0)
DRIVE
SELECTED
0
0
1
1
0
1
0
1
None
1
2
3
Normal Floppy Mode
Normal mode.Register 3F3 contains only bits 0 and 1. When this register is read, bits 2 – 7 are ‘0’.
DB7
0
DB6
0
DB5
0
DB4
0
DB3
0
DB2
0
DB1
DB0
REG 3F3
tape sel1 tape sel0
Enhanced Floppy Mode 2 (OS2)
Register 3F3 for Enhanced Floppy Mode 2 operation.
DB7
DB6
DB5
Drive Type ID
DB4
DB3
Floppy Boot Drive
DB2
DB1
DB0
REG 3F3 Reserved Reserved
tape sel1 tape sel0
Table 6.6 - Drive Type ID
DIGITAL OUTPUT REGISTER REGISTER 3F3 – DRIVE TYPE ID
Bit 1
Bit 0
Bit 5
Bit 4
0
0
1
1
0
1
0
1
L0-CRF2 – B1
L0-CRF2 – B3
L0-CRF2 – B5
L0-CRF2 – B7
L0-CRF2 – B0
L0-CRF2 – B2
L0-CRF2 – B4
L0-CRF2 – B6
Note: L0-CRF2-Bx = FDC Logical Device, Configuration Register F2, Bit x.
Revision 1.8 SMSC/Non-SMSC Register Sets (02-24-05)
44
SMSC LPC47M182
DATASHEET
SMSC [ SMSC CORPORATION ]
