SMSC Defined Logical Device Configuration Registers
The SMSC Specific Logical Device Configuration Registers reset to their default values only on hard resets
generated by Vcc POR or VTR POR or VBAT POR (as shown) or the RESET_DRV signal. These
registers are not affected by soft resets.
Table 68 - Floppy Disk Controller, Logical Device 0 [Logical Device Number = 0x00]
NAME
REG INDEX
DEFINITION
STATE
FDD Mode Register
0xF0 R/W Bit[0] Floppy Mode
C
= 0
= 1
Normal Floppy Mode (default)
Enhanced Floppy Mode 2 (OS2)
Default = 0x0E
Bit[1] FDC DMA Mode
on Vcc POR or
Reset_Drv
= 0
= 1
Burst Mode is enabled
Non-Burst Mode (default)
Bit[3:2] Interface Mode
= 11
= 10
= 01
= 00
AT Mode (default)
(Reserved)
PS/2
Model 30
Bit[4] Swap Drives 0,1 Mode
= 0
= 1
No swap (default)
Drive and Motor sel 0 and 1 are swapped.
Bits[5] Reserved, set to zero.
Bit [6] Output Type Control:
0= FDC outputs are OD24 open drain (default)
1= FDC outputs are O24 push-pull.
Bit [7] FDC output Control:
0= FDC outputs active (default)
1= FDC outputs tristated
Note: these bits do not affect the parallel port FDC
pins.
FDD Option Register
Default = 0x00
0xF1 R/W Bits[1:0] Reserved, set to zero
Bits[3:2] Density Select
C
= 00
= 01
= 10
= 11
Normal (default)
Normal (reserved for users)
1 (forced to logic "1")
0 (forced to logic "0")
on Vcc POR or
Reset_Drv
Bit[5:4] Reserved, set to zero
Bits[7:6] Boot Floppy
= 00
= 01
= 10
FDD 0 (default)
FDD 1
Reserved (neither drive A or B is a boot
drive).
= 11
Reserved (neither drive A or B is a boot
drive).
175
SMSC [ SMSC CORPORATION ]
