PC87307VUL National Semiconductor, PC87307VUL Datasheet - Page 89

• Manufacturer Part Number: PC87307VUL
• Description: PC87307/PC97307 Plug and Play Compatible and PC97 Compliant SuperI/O
• Manufacturer: National Semiconductor

First through Fourth Result Phase Bytes, Bits 7-0,
Present Track Number (PTR) Drives 3-0
Fifth and Sixth Result Phase Bytes, Bits 7-0,
Step Rate Time, Motor Off Time, Motor On Time and
DMA
Seventh Result Phase Byte -
Sectors Per Track or End of Track (EOT)
Eighth Result Phase Byte
Bits 5-0 - DC3-0, GDC
Bit 7 - LOCK
LOCK
7
0
Step Rate Time (SRT)
Each of these bytes contains either the internal 8-bit
track number or the least significant byte of the 12-bit
track number of the corresponding logical disk drive.
These fields are all set by the SPECIFY command. See
Section 5.7.21 on page 105.
This byte varies depending on what commands have
been previously executed.
If the last command issued was a FORMAT TRACK
command, and no read or write commands have been
issued since then, this byte contains the sectors per
track value.
If a read or a write command was executed more recent-
ly than a FORMAT TRACK command, this byte speci-
fies the number of the sector at the End of the Track
(EOT).
Bits 5-0 of the second command phase byte of the PER-
PENDICULAR MODE command set bits 5-0 of this byte.
See page 95.
This bit controls how the other bits in this command re-
spond to a software reset. See page 92.
The value of this is determined by bit 7 of the opcode of
the LOCK command.
0 -Bits in this command are set to their default values
1 - Bits in this command are unaffected by a software
Sectors per Track or End of Track (EOT) Sector #
Byte of Present Track Number (PTR) Drive 0
Byte of Present Track Number (PTR) Drive 1
Byte of Present Track Number (PTR) Drive 2
Byte of Present Track Number (PTR) Drive 3
after a software reset. (Default)
reset.
Precompensation Track Number (PRETRK)
EIS
6
0
Delay Before Processing
FIFO POLL
DC3
5
DC2
4
DC1
3
Delay After Processing
DC0
THRESH
2
1
GDC
DMA
0
89
Ninth and Tenth Result Phase Bytes
5.7.4
This command formats one track on the disk in IBM, ISO, or
Toshiba perpendicular format.
After a pulse from the INDEX signal is detected, data pat-
terns are written on the disk including all gaps, Address
Marks (AMs), address fields and data fields. See Figure
5-20.
The format of the track is determined by the following pa-
rameters:
Table 5-10 shows typical values for these parameters for
specific PC compatible diskettes.
To allow flexible formatting, the microprocessor must sup-
ply the four address field bytes (track number, head num-
ber, sector number, bytes-per-sector code) for each sector
formatted during the execution phase. This allows non-se-
quential sector interleaving.
This transfer of bytes from the microprocessor to the con-
troller can be done in DMA or non-DMA mode (See Section
5.4.2 on page 78), with the FIFO enabled or disabled.
The FORMAT TRACK command terminates when a pulse
from the INDEX signal is detected a second time, at which
point an interrupt is generated.
Command Phase
•
•
•
•
•
•
X
7
0
These bytes reflect the values in the third and fourth
command phase bytes of the CONFIGURE command.
See page 88.
The MFM bit in the opcode (first command) byte, which
indicates the type of the disk drive and the data transfer
rate and determines the format of the address marks
and the encoding scheme.
The Index Address Format (IAF) bit (bit 6 in the second
command phase byte) in the MODE command, which
selects IBM or ISO format.
The Group Drive Configuration (GDC) bits in the PER-
PENDICULAR MODE command, which select either
conventional or Toshiba perpendicular format.
A bytes-per-sector code, which determines the sector
size. See Table 5-11 on page 90.
A sectors per track parameter, which specifies how
many sectors are formatted on the track.
The data pattern byte, which is used to fill the data field
of each sector.
MFM
The FORMAT TRACK Command
X
6
X
5
0
Bytes-Per-Sector Code
Sectors per Track
Bytes in Gap 3
Data Pattern
X
4
0
X
3
1
HD
2
1
DS1
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1
0
DS0
0
1