PC87332VLJ-5 NSC [National Semiconductor], PC87332VLJ-5 Datasheet - Page 48

• Manufacturer Part Number: PC87332VLJ-5
• Description: PC87332VLJ (3.3V/5V) and PC87332VLJ-5 (5V) (SuperI/OTM III Premium Green) Floppy Disk Controller, Dual UARTs, IEEE1284 Parallel Port, and IDE Interfac
• Manufacturer: NSC [National Semiconductor]

4 0 FDC Command Set Description
Note Motor Off Time
Note Motor On Time
The Motor Off and Motor On timers are artifacts of the NEC
lecting a drive motor until a read or write operation is start-
ed and the delay of deselecting the drive motor after the
command is completed Since the FDC enables the drive
and motor select line directly through the DOR these timers
only provide some delay from the initiation of a command
until it is actually started
4 1 21 Verify Command
The Verify command reads logical sectors containing a Nor-
mal Data AM from the selected drive without transferring
the data to the host This command is identical to the Read
Data command except that no data is transferred during
the Execution Phase
The Verify command is designed for post-format or post-
write verification Data is read from the disk as the control-
ler checks for valid Address Marks in the Address and Data
Fields The CRC is computed and checked against the pre-
viously stored value on the disk The EOT value should be
set to the final sector to be checked on each side If EOT is
greater than the number of sectors per side the command
will terminate with an error and no useful Address Mark or
CRC data will be given
The TC pin cannot be used to terminate this command
since no data is transferred The verify command can simu-
late a TC by setting the EC bit to a 1 In this case the
command will terminate when SC (Sector Count) sectors
have been read (If SC
fied ) If EC
PD765 These timers determine both the delay from se-
Data Rate
Data Rate
500 kbps
300 kbps
250 kbps
500 kbps
300 kbps
250 kbps
1 Mbps
1 Mbps
e
0 then the command will terminate when
e
e
0 is treated as MFT
0 is treated as MNT
MFT
e
MFT
MFT
MNT
MFT
MNT
Value
0 then 256 sectors will be veri-
Value
c
MNT
MNT
c
c
c
Mode 1 (TMR
c
80 3
Mode 1 (TMR
c
16
32
10 3
8
4
e
e
16
128
TABLE 4-17 Motor Off Time (MFT) Values
TABLE 4-18 Motor On Time (MNT) Values
e
e
26 7–427
0)
16–256
32–512
Range
8–128
0)
3 3–427
Range
1–128
1–128
4–512
(Continued)
48
EOT is equal to the last sector to be checked In this case
the Data Length parameter should be set to FFh Refer to
Table 4-10 for the Result Phase values for a successful
completion of the command Also see Table 4-19 for further
explanation of the result bytes with respect to the MT and
EC bits
Command Phase
Execution Phase Data is read from disk but not transferred
to the system
Result Phase
MFT
MT
EC
MFT
MFT
MFT
MNT
MNT
MNT
MNT
Value
c
c
Value
c
c
2560 3
c
MFM
1024
512
512
c
c
c
Mode 2 (TMR
X
Mode 2 (TMR
160 3
32
32
64
End of Track Sector Number
Data Length Sector Count
SK
X
Intersector Gap Length
Drive Head Number
Status Register 0
Status Register 1
Status Register 2
Bytes per Sector
Bytes per Sector
Sector Number
Sector Number
Track Number
Track Number
Head Number
e
1
X
e
1024– 16384
853– 13653
1)
512 – 8192
512 – 8192
1)
32 – 4096
32 – 4096
53– 6827
64 – 8192
Range
Range
0
X
HD
1
DR1
1
Units
Units
ms
ms
ms
ms
ms
ms
ms
ms
DR0
0