values only on hard resets generated by Vcc or
VTR POR (as shown) or the RESET_DRV
signal. These registers are not affected by soft
resets.
SMSC Defined Logical Device Configuration
Registers
The
SMSC
Specific
Logical
Device
Configuration Registers reset to their default
Table 81 - 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 Normal Floppy Mode (default)
= 1 Enhanced Floppy Mode 2 (OS2)
Bit[1] FDC DMA Mode
Default = 0x0E
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[7:5] Reserved, set to zero.
FDD Option
Register
0xF1 R/W Bits[1:0] Reserved, set to zero
Bits[3:2] Density Select
C
= 00
= 01
= 10
= 11
Normal (default)
Default = 0x00
Normal (reserved for users)
1 (forced to logic "1")
0 (forced to logic "0")
on Vcc POR or
Reset_Drv
Bit[4] Media ID 0 Polarity
= 0: Don’t invert (default)
= 1: Invert
Bit[5] Media ID 1 Polarity
= 0: Don’t invert (default)
= 1: Invert
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).
188
SMSC [ SMSC CORPORATION ]
