PC87332VLJ-5 NSC [National Semiconductor], PC87332VLJ-5 Datasheet - Page 35

• 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
The sixth byte of the result phase varies depending on what
commands have been previously executed If a format com-
mand has previously been issued and no reads or writes
have been issued since then this byte contains the Sectors
per track value If a read or a write command has been
executed more recently than a format command this byte
contains the End of Track value The LOCK bit is set in the
Lock command The eighth result byte also contains the bits
programmed in the Perpendicular Mode command The last
two bytes of the Dumpreg Result Phase are set in the Con-
figure command After a hardware or software reset the
parameters in the result bytes are set to their appropriate
default values
Note Some of these parameters are unaffected by a software reset de-
Command Phase
Execution Phase Internal registers read
Result Phase
Note Sectors per Track parameter returned if last command issued was
4 1 3 Format Track Command
This command formats one track on the disk in IBM ISO or
Perpendicular format After the index hole is detected data
patterns are written on the disk including all gaps Address
Marks Address Fields and Data Fields The exact format is
determined by the following parameters
1 The MFM bit in the Opcode (first command) byte which
2 The IAF bit in the Mode command which selects be-
3 The WGATE and GAP bits in the Perpendicular Mode
LOCK
determines the format of the Address Marks and the en-
coding scheme
tween IBM and ISO format
command which select between the conventional and
Toshiba Perpendicular format
0
0
pending on the state of the LOCK bit See the Lock Command for
further information
Format End of Track parameter returned if last command issued was
Read or Write
Step Rate Time
EIS
0
0
Sector per Track End of Track (Note)
FIFO
DC3
0
Motor On Time
POLL
DC2
PTR Drive 0
PTR Drive 1
PTR Drive 2
PTR Drive 3
0
PRETRK
DC1
1
Motor Off Time
DC0
1
THRESH
GAP
1
DMA
WG
0
(Continued)
35
4 The Bytes per Sector code which determines the sector
5 The Sector per Track parameter which determines how
6 The Data Pattern byte which is used as the filler byte in
Command Phase
Execution Phase System transfers four ID bytes (track
head sector bytes sector) per sector to the floppy control-
ler via DMA or Non-DMA modes The entire track is format-
ted The data block in the Data Field of each sector is filled
with the data pattern byte
Result Phase
To allow for flexible formatting the P must supply the four
Address Field bytes (track head sector bytes per sector
code) for each sector formatted during the Execution
Phase This allows for non-sequential sector interleaving
This transfer of bytes from the P to the controller can be
done in the DMA or Non-DMA mode with the FIFO enabled
or disabled
The Format Gap byte in the Command Phase is dependent
on the data rate and type of disk drive and controls the
length of GAP3 Some typical values for the programmable
GAP3 are given in Table 4-1 Figure 4-2 shows the track
format for each of the formats recognized by the format
command Table 4-2 shows some typical values for the For-
mat GAP3 based on media type The Format command ter-
minates when the index hole is detected a second time at
which point an interrupt is generated Only the first three
status bytes in the Result Phase are significant
0
X
size
many sectors are formatted on the track
the Data Field of each sector
MFM
X
X
0
Sectors per Track
Status Register 0
Status Register 1
Status Register 2
Bytes per Sector
0
X
Data Pattern
Format Gap
Undefined
Undefined
Undefined
Undefined
1
X
HD
1
DR1
0
DR0
1