Advanced I/O Controller with Motherboard GLUE Logic
Datasheet
6.20 Sense Drive Status
Sense Drive Status obtains drive status information. It has not execution phase and goes directly to the
result phase from the command phase. Status Register 3 contains the drive status information.
6.21 Specify
The Specify command sets the initial values for each of the three internal times. The HUT (Head Unload
Time) defines the time from the end of the execution phase of one of the read/write commands to the head
unload state. The SRT (Step Rate Time) defines the time interval between adjacent step pulses. Note that
the spacing between the first and second step pulses may be shorter than the remaining step pulses. The
HLT (Head Load Time) defines the time between when the Head Load signal goes high and the read/write
operation starts. The values change with the data rate speed selection and are documented in Table 6.26.
The values are the same for MFM and FM.
DMA operation is selected by the ND bit. When ND is “0”, the DMA mode is selected. This part does not
support non-DMA mode. In DMA mode, data transfers are signaled by the DMA request cycles.
6.22 Configure
The Configure command is issued to select the special features of the FDC. A Configure command need
not be issued if the default values of the FDC meet the system requirements.
Table 6.26 - Drive Control Delays (ms)
HUT
SRT
2M
64
4
1M
128
8
500K 300K 250K
2M
4
3.75
..
0.5
0.25
1M
8
7.5
..
1
0.5
500K 300K 250K
0
1
..
E
F
256
16
426
26.7
..
512
32
16
15
..
26.7
25
32
30
..
..
..
..
..
..
56
60
112
120
224
240
373
400
448
480
2
3.33
1.67
4
1
2
HLT
2M
64
0.5
1
1M
128
1
500K
256
2
4
..
300K
250K
512
4
8
.
00
01
02
..
7F
7F
426
3.3
6.7
..
2
..
..
63
63.5
126
127
252
254
420
423
504
508
6.22.1 Configure Default Values:
EIS - No Implied Seeks
EFIFO - FIFO Disabled
POLL - Polling Enabled
FIFOTHR - FIFO Threshold Set to 1 Byte
PRETRK - Pre-Compensation Set to Track 0
EIS - Enable Implied Seek. When set to "1", the FDC will perform a Seek operation before executing a read
or write command. Defaults to no implied seek.
SMSC LPC47M182
73
Revision 1.8 SMSC/Non-SMSC Register Sets (02-24-05)
DATASHEET
SMSC [ SMSC CORPORATION ]
