參數(shù)資料
型號(hào): L6000
廠商: 意法半導(dǎo)體
英文描述: SINGLE CHIP READ & WRITE CHANNEL
中文描述: 單芯片讀
文件頁(yè)數(shù): 20/24頁(yè)
文件大?。?/td> 279K
代理商: L6000
1.7 RLL ENCODING
Previuos RLL
Code Word
Last Bits
X
X
X
X
1
1
0
0
X
X
X
X
Y2’
NRZ Data Bits
Present
1
1
1
1
0
0
0
0
0
0
0
0
D1
X = Do Not Care
* = Not AllZeros
1, 7 RLL CODE SET
Next
0
1
0
*
0
1
0
1
0
1
0
*
D3
RLL
Code Bits
1
1
0
1
0
0
0
0
0
0
0
0
Y1
Y2
0
0
0
0
0
0
0
0
1
1
1
1
Y3
0
0
1
1
0
0
1
1
0
0
1
1
D2
X
X
0
*
X
X
X
X
X
X
0
*
D4
0
1
1
0
0
0
0
0
0
1
1
0
1
0
0
0
1
0
1
0
1
0
0
0
Y3
ReadMode
The phase comparator enters its phaseonly com-
pare mode after three cycles of a 3T pattern.This
means that the leading edge of
arms the comparator and then the phase com-
parison is done between the trailing edge of
READ DATA and the rising edge of the closest
VCO cycle. The time between the two READ
DATA edges is 1 VCO cycle, or 1/3 bit cell and is
generated by an internal one-shot and the PLL
ControlDAC.
The Window Shift function of the L6000 is pro-
vided for testing purposes, and advanced recov-
ery from read errors. To shift the bit position from
its nominal centerd position in the decode win-
dow, a value is written to the WinShift register via
the serial interface. The shift value will take effect
after SERIAL ENABLE is deasserted. The direc-
tion is determined by the Direction bit in the regis-
ter. See the Register Definition section for the
complete set of values and their effect. To do the
Windowshift function, the WinShift registersets a
current in the WS DAC wich than adds or sub-
tracts current in the 1/2 VCO cycle delay for the
Data Synchronizer. This then changes the posi-
tion of the trailing edge of the READ DATA pulse
at the Synchronizer ONLY. Since the edge posi-
tion doesn’t change relative to the VCO at the
phase lock is unaffected,and only the bit position
is moved inside the decode window in the Syn-
chronizer.
The VCO has a zero phase restart feature which
allows for very quick acquisition of the READ
DATA phase being recovered from the disk. The
VCO is kept at frequency Fout during Idle mode,
and when Preamble is detected, the zero phase
restart first turn OFF the VCO, then restarts it in
phasewith the first received databit.
READ DATA
ABOVEVOLTAGEMONITOR
The above voltage bit is used to actively center
the bit in the window by trimming the operating
current of PLL Control DAC to its midpoint of op-
eration.
To optimize this time from temperature and proc-
ess variations, the Above Voltage check should
be performed on a periodic (at least every fre-
quency switch) basis. This will center the operat-
ing point of the VCO and set the 1/2 VCO cycle
delaycloset to nominal.
Above Voltage monitor bit (Register 4, B7):
This feature allows the drive microprocessor to
set the VCO to the center of its capture range,
and to remove any offset error from the delay
one-shots in the Data Separator. By changingthe
setting of the VCO center register (04), the drive
microprocessor caN maxime the loop lock range
(and minimize margin timing error at power up).
The comparator driving this bit allows for setting
the VCO DAC (Register 04) to place the Data
Separator VFO to its mid-point of operation. It is
intended for use a power-up time calibration, but
can be done at any time power is applied to the
L6000.The microprocessor which loadsthe regis-
ter values monitors this bit in the following algo-
rithm:
1.Set the Numerator and Denominator values
for the first data rate in Register 0E and 06,
respectively.
2. Write the nominal value chosen to the VCO,
DAC, Register 04.
3.Read the Above Voltage bit: if it is HIGH, de-
crease the value in Register 04 by 1. If it is
LOW, increase the value in Register04 by 1.
4.Read the bit again; if it has reversed polarity
store the value written to Register 04 as the
Calibrated VCO DAC Register 2 value for fu-
ture use when in that zone. If it has not, re-
peat step3.
5.Repeat the same procedure (steps 1 to 4) for
all zones and store the Calibrated Register 2
values for futureuse.
Soft Sector- ReadBack
The assertion of READ GATE initiates the lock up
sequence. The lock up sequence proceedes as
follows:
1.An Address Mark is searched for. The Ad-
dress Mark consists of two sets of 7 0s, 1, 11
0s, 1, 11 0s,1. When the L6000 detects6 0s,
then detects 9 0s, TWICE, it generates the
Address Mark found condition, and asserts
ADDRMARK DET. ADDRMARK DET will re-
main asserted until the end of the Read op-
eration. If the 9 0s are not detected within 5
data bits of the 6 0s field, the circuit will auto-
L6000
20/24
相關(guān)PDF資料
PDF描述
L602-L604 DARLINGTON ARRAYS
L601 DARLINGTON ARRAYS
L601-L603 DARLINGTON ARRAYS
L603 DARLINGTON ARRAYS
L603C DARLINGTON ARRAYS
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L60000 制造商:LAUREL ELECTRONICS 功能描述:Laureate 1/8 DIN serial input meter / remote display, universal 85-264 Vac power
L60000FR 制造商:LAUREL ELECTRONICS 功能描述:MULTIFUNCTION COUNTER 制造商:LAUREL ELECTRONICS 功能描述:MULTIFUNCTION COUNTER; No. of Digits / Alpha:6; Digit Height:14.2mm; Panel Cutout Height:45mm; Panel Cutout Width:92mm; Operating Temperature Min:0C; Operating Temperature Max:60C; Character Size:0.56"; Display Font Color:Red ;RoHS Compliant: Yes
L60001FR 制造商:LAUREL ELECTRONICS 功能描述:Laureate 1/8 DIN multi-function counter / timer, universal 85-264 Vac power, no relays, no analog output, RS232 communications, dual pulse inputs for frequency, rate, rotal, or timing. ;RoHS Compliant: Yes
L60002 制造商:Honeywell Sensing and Control 功能描述: 制造商:SKAN-A-MATIC 功能描述: 制造商:LAUREL ELECTRONICS 功能描述:Laureate 1/8 DIN serial input meter / remote display, universal 85-264 Vac power
L60002VF1 制造商:LAUREL ELECTRONICS 功能描述:Laureate 1/8 DIN multi-function counter / timer, universal 85-264 Vac power, no