PS/2 Model 30 Interface Mode
Table 6 - SRA PS/2 Model 30 Mode
7
6
5
4
3
2
1
0
INT
DRQ
STEP F/F TRK0
nHDSEL
INDX
WP
nDIR
PENDING
RESET
0
0
0
N/A
1
N/A
N/A
1
CONDITION
nDIRECTION, Bit 0
Active low status indicating the direction of head movement. A logic “0” indicating inward direction a logic “1” outward.
Write Protect, Bit 1
Active high status of the WRITE PROTECT disk interface input. A logic “1” indicating that the disk is write protected.
The nWRITE PROTECT bit also depends upon the state of the Force Write Protect bits in the Force FDD Status
Change configuration register (see section CR17 on page 109).
Index, Bit 2
Active high status of the INDEX disk interface input.
nHEAD SELECT, Bit 3
Active low status of the HDSEL disk interface input. A logic “0” selects side 1 and a logic “1” selects side 0.
Track, Bit 4
Active high status of the TRK0 disk interface input.
Step, Bit 5
Active high status of the latched STEP disk interface output pin. This bit is latched with the STEP output going active,
and is cleared with a read from the DIR register, or with a hardware or software reset.
DMA Request, Bit 6
Active high status of the DRQ output pin. Interrupt Pending, Bit 7 Active high bit indicating the state of the Floppy
Disk Interrupt output.
SMSC DS – FDC37N3869
Page 20
Rev. 10/25/2000
SMSC [ SMSC CORPORATION ]
