FDC37C672QFP SMSC Corporation, FDC37C672QFP Datasheet - Page 58

• Manufacturer Part Number: FDC37C672QFP
• Description: ENHANCED SUPER I/O CONTROLLER WITH FAST IR
• Manufacturer: SMSC Corporation

8.2.7
SMSC FDC37C672
The choice of DMA or non-DMA operations is made by the ND bit. When this bit is "1", the non-DMA
mode is selected, and when ND is "0", the DMA mode is selected. In DMA mode, data transfers are
signaled by the FDRQ pin. Non-DMA mode uses the RQM bit and the FINT pin to signal data transfers.
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.
00
01
02
7F
7F
E
F
0
1
..
..
2M
64
56
60
4
..
63.5
2M
0.5
64
63
1
..
128
112
120
1M
8
..
500K
Table 8.10 - Drive Control Delays (ms)
256
224
240
16
..
HUT
128
126
127
1M
1
2
..
DATASHEET
300K
26.7
426
373
400
..
250K
Page 58
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
Enhanced Super I/O Controller with Fast IR
SRT
300K
26.7
3.33
1.67
25
..
250K
512
504
508
4
8
.
250K
32
30
..
4
2
Rev. 10-29-03
Datasheet