L6000 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L6000' PDF : 24 Pages View PDF
L6000
for the generation of the Address Mark and
19 cycles 3T patterns of preamble (the pre-
amble’s minimum lenght).
2.WRITE CLOCK should be present and READ
REF CLOCK can be used if the propagation
delay relative to WRT DATA NRZ IN is short.
3.First TWO Address Marks of 7 0s, 1, 7 0s, 1,
11 0s, 1, 11, 0s are output from the WRITE
DATA pin.
4.Next 19 3T patterns (0 1 0 ) are written.
5.At this point, WRT DATA NRZ IN should be
active and inputting the disk data to be writ-
ten. For a longer Preamble, hold WRT DATA
NRZ IN low and more 3T patterns will be gen-
erated.
6.WRITE GATE must be held asserted until all
data is output from the (1, 7) Encoder. There
is a maximum of 15 bits delay, so WRITE
GATE should not deassert until after data has
been flushed from the Encoder.
Hard Sector - Write
The Hard Sector write operation is identical to the
Soft sector, except that at the start, no Address
Mark is generated. WRT DATA NRZ IN should be
held low (rather than have 80 or FF at the start).
The appropriate tables for write precompensation
are:
WRITE PRECOMPENSATION ALGORITHM
RLL Bit Pattern:
Compensation
N-2 N-1 N N+1 N+2
1
0
1
0
1
0
0
1
0
0
1
0
1
0
0
0
0
1
0
1
BIT N
NONE
NONE
EARLY
LATE
LATE: Bit N is time shifted (delayed) from its normal
time position towards the Bit N+1 time position
EARLY: Bit N is time shifted (Advanced) from its nor-
mal time position towards the Bit N-1 time position
Write Precompensation Control
Write precompensation magnitude is set using
the Write Precompensation register. The write
precompensation register bits are defined as fol-
lows:
Bit Symbol
Description
0
WO
Write Precomp LSB
1
W1
Write Precomp
2
W2
Write Precomp MSB
3
WPE Write Precomp Enable
4-7 Unused
W2, W1, W0 - Write precomp magnitude control
bits:
000 > 7x (maximum) shift
001 > 6x shift
010 > 5x shift
011 > 4x shift
100 > 3x shift
101 > 2x shift
110 > 1x shift
111 > No shift
Test Mode
This part has a secondary Write mode. When the
Direct Write bit is set in the Control B register, the
waveform present on the WRT DATA NRZ IN pin
is passed directly through the L6000 to the
preamp WDI pin. This allows for operations like
servowriting to be done with the drive PCB at-
tached to the mechanics. Care should be taken
with the bit in normal system operation.
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