LPC47S457-NC SMSC [SMSC Corporation], LPC47S457-NC Datasheet - Page 59

• Manufacturer Part Number: LPC47S457-NC
• Description: Advanced I/O with X-Bus Interface
• Manufacturer: SMSC [SMSC Corporation]

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.
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.
EFIFO - A "1" disables the FIFO (default). This means data transfers are asked for on a byte-by-byte basis. Defaults to
"1", FIFO disabled. The threshold defaults to "1".
POLL - Disable polling of the drives. Defaults to "0", polling enabled. When enabled, a single interrupt is generated
after a reset. No polling is performed while the drive head is loaded and the head unload delay has not expired.
FIFOTHR - The FIFO threshold in the execution phase of read or write commands. This is programmable from 1 to 16
bytes. Defaults to one byte. A "00" selects one byte; "0F" selects 16 bytes.
PRETRK - Pre-Compensation Start Track Number. Programmable from track 0 to 255. Defaults to track 0. A "00"
selects track 0; "FF" selects track 255.
Version
The Version command checks to see if the controller is an enhanced type or the older type (765A). A value of 90 H is
returned as the result byte.
SMSC DS – LPC47S45x
7F
7F
00
01
02
E
0
1
..
F
..
2M
64
56
60
4
..
63.5
2M
0.5
64
63
1
..
128
112
120
1M
8
..
500K
256
224
240
Table 26 − Drive Control Delays (ms)
16
..
HUT
128
126
127
1M
1
2
..
DATASHEET
300K
26.7
426
373
400
..
Page 59 of 259
250K
512
448
480
32
..
500K
256
252
254
2
4
..
3.75
0.25
2M
0.5
4
..
HLT
1M
7.5
0.5
8
..
1
300K
426
420
423
3.3
6.7
..
500K
16
15
2
1
..
SRT
300K
26.7
3.33
1.67
25
..
250K
512
504
508
4
8
.
250K
32
30
4
2
..
Rev. 07/09/2001