
IT8673F
1
11.4.12.7
The LOCK command allows the programmer to fully control the FIFO parameters after a hardware reset. If
the LOCK bit is set to 1, the parameters DFIFO, FIFOTHR, and PRETRK in the CONFIGURE command are
not affected by a software reset. If the bit is set to 0, those parameters are set to default values after a
software reset.
LOCK
11.4.12.8
The VERSION command is used to determine the controller being used. In Result phase, a value of 90 hex
is returned in order to be compatible with the 82077.
VERSION
11.4.12.9
The SENSE INTERRUPT STATUS command resets the interrupt signal (IRQ) generated by the FDC, and
identifies the cause of the interrupt via the IC code and SE bit of the ST0, as shown in Table 11-19.
It may be necessary to generate an interrupt when any of the following conditions occur:
1. Before any Data Transfer or READ ID command
2. After SEEK or RE-CALIBRATE commands (no result phase exists)
3. When a data transfer is required during an Execution phase in the non-DMA mode
SENSE INTERRUPT STATUS
Table 11-19. Interrupt Identification
SE
IC Code
Cause of Interrupt
0
11
Polling.
1
00
Normal termination of SEEK or RE-CALIBRATE command.
1
01
Abnormal termination of SEEK or RE-CALIBRATE command.
11.4.12.10 SENSE DRIVE STATUS
The SENSE DRIVE STATUS command acquires drive status information. It has no Execution phase.
11.4.12.11 SPECIFY
The SPECIFY command sets the initial values for the HUT (Head Unload Time), HLT (Head Load Time),
SRT (Step Rate Time), and ND (Non-DMA mode) parameters. The possible values for HUT, SRT, and HLT
are shown in Table 11-20, Table 11-21 and Table 11-22 respectively. The FDC is operated in DMA or
non-DMA mode based on the value specified by the ND parameters.
Table 11-20. HUT Values
Parameter
0
1 Mbps
128
500 Kbps
256
300 Kbps
426
250 Kbps
512
1
8
16
26.7
32
…
…
…
…
…
E
112
224
373
448
F
120
240
400
480