FDC37N869 View Datasheet(PDF) - SMSC -> Microchip
Part Name
Description
MFG CO.
FDC37N869
SMSC -> Microchip
'FDC37N869' PDF : 147 Pages View PDF
Enhanced Floppy Mode 2 (OS2)
The configuration of the TDR in the Enhanced Floppy Mode 2 (OS/2 mode) is shown in Table 14.
TDR
DB7
Table 14 - TDR Enhanced Floppy Mode 2
DB6
DB5
DB4
DB3
DB2
Reserved
Drive Type ID
Floppy Boot Drive
DB1
Tape
Sel1
DB0
Tape
Sel0
Reserved, Bits 6 - 7
Bits 6 and 7 are RESERVED. Reserved bits cannot be written and return 0 when read.
Drive Type ID, Bits 4 - 5
The Drive Type ID bits depend on the last drive selected in the Digital Output Register and the Drive Type IDs that
are programmed in configuration register 6 (Table 15).
Table 15 - Drive Type ID
DIGITAL OUTPUT REGISTER
TDR - DRIVE TYPE ID
Bit 1
Bit 0
Bit 5
Bit 4
0
0
CR6 - Bit 1
CR6 - Bit 0
0
1
CR6 - Bit 3
CR6 - Bit 2
1
0
CR6 - Bit 5
CR6 - Bit 4
1
1
CR6 - Bit 7
CR6 - Bit 6
Floppy Boot Drive, Bits 2 - 3
The Floppy Boot Drive bits come from Configuration Register 7: TDR Bit 3 = CR7 Bit 1; TDR Bit 2 = CR7 Bit 0.
Tape Drive Select, Bits 0 - 1
The Tape Drive Select bits are the same as in Normal mode. These bits are Read/Write.
MAIN STATUS REGISTER (MSR)
The Main Status Register (Base Address + 4: Read-only) indicates the status of the disk controller (Table 16). The
Main Status Register is valid in all modes and can be read at any time. The MSR indicates when the disk
controller is ready to receive data via the Data Register. It should be read before transferring each byte to or from
the data register, except in DMA mode. No delay is required when reading the MSR after a data transfer.
MSR
7
RQM
Table 16 - Main Status Register
6
5
4
3
DIO NON DMA CMD
BUSY
DRV3
BUSY
2
DRV2
BUSY
1
DRV1
BUSY
0
DRV0
BUSY
DRVx Busy, Bits 0 - 3
These bits are set to a “1” when a drive is in the seek portion of a command, including implied and overlapped
seeks and recalibrates.
SMSC DS – FDC37N869
Page 25
Rev. 11/09/2000
Share Link: 