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參數(shù)資料
| 型號(hào)： | LM9830 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | LM9830 36-Bit Color Document Scanner |
| 中文描述： | LM9830 36位彩色文件掃描儀 |
| 文件頁數(shù)： | 28/45頁 |
| 文件大?。?/td> | 566K |
| 代理商： | LM9830 |
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Paused until a Resume Scan signal is received. During the hold
current timeout period, the DAC output is held at 0.125V (the
hold current) for FullStep mode, or the DAC outputs are held as
they were prior to stopping for the microstep mode. After the
hold current timeout period, output drivers A, B, A, and B are
deasserted.
Wait for Resume Scan signal
Wait for correct number of pixel periods to resynchronize step-
per motor with sensor timing.
25% speed forward for y steps (1 step = 4*#pixels in
Scanning
Step Size
register)
50% speed forward for z steps (1 step = 2* #pixels in
Scanning
Step Size
register).
Full speed forward (1 step = #pixels in
Scanning Step Size
register), with TR pulses synchronized to same the position on
image that they would have been had scanner not stopped.
The
Lines to Process After Pause Scan Signal
/
Lines to Dis-
card After Resume Scan Signal
register is not used in reversing
mode.
3.5 Fast Feed Step Size Register
When the motor is being moved quickly (
Paper Feed to
End
/
Paper Feed to Beginning
command or
Steps to Skip at
Start of Scan
register), the microstep period comes from this
register.
For all other motor movement, the step size is given in the
Scan-
ning Step Size
register.
3.6 Stepper Motor Current Control Using PWM
There is an option to use Pulse Width Modulation of the current in
the stepper motor to increase high speed torque, optimize effi-
ciency, and allow use of a lower current, less expensive motor.
Precisely controlling the current in the motor provides several
benefits. In Full Step Mode, the motor can start moving faster and
overcome inertia by increasing the current to the motor to 100%
when it is starting from a dead stop. After a programmable num-
ber of steps, the inertia is overcome and the current can be
reduced to 66% to reduce heat in the stepper motor (allowing a
less expensive motor to be used). When stopping the stepper
motor, the current is increased to 100% for a short time to over-
come the forward momentum, then the motor is held in position
with a low-level standby current of 30-40%. If the motor is motion-
less for more than the Hold Current Timeout period, the current
goes to 0%.
In microstepping mode, the PWM is used to approximate a sine
wave as shown in Figure 18.
The current control is accomplished by measuring the average
motor winding current through a sense resistor to ground, com-
paring it to a reference voltage, and PWMing the motor driver
transistor to force the current to be equal to the reference current.
See the
Stepper Motor Current Controller Block Diagram
at
the end of this document.
4.0 Scanner Support Functions
4.1 Illumination Control Block
Scanner systems require an illumination source to supply the
light to the image being scanned. This source may be white (typi-
cally a fluorescent lamp), or red, green, and/or blue LEDs. There
are four illumination modes in the LM9830:
In Illumination Mode 1, the lamp connected to the LAMP
R
pin is
controlled by the LAMP
R
On/Off settings in the configuration reg-
ister. The LAMP
B
output (if used) is controlled the same way. If
the lamp is supposed to be on all the time, then the On setting
should be set to a number between 0 and the value in the Line
End register, and the Off register should be set to a number
greater than the value in the Line End register. Conversely, if the
lamp is supposed to be off all the time, then the On setting should
be set to a number greater than the value in the Line End register,
and the Off register should be set to a number between 0 and the
value in the Line End register. The LAMP
G
output is a Pulse-
Width-Modulated pulse stream whose duty cycle is controlled by
the value in the PWM register (0-4095). The duty cycle is there-
fore equal to the register value/4096. The PWM counter is
clocked with the CRYSTAL IN frequency so the output frequency
is CRYSTAL IN/4096 (12.2kHz with a 50MHz clock). This PWM
output can be used to control the brightness of a fluorescent
lamp.
In Illumination Mode 2 (which is typically used in conjunction with
1 Channel Mode B
), the LAMP
R
, LAMP
G
, and LAMP
B
outputs
are cycled through sequentially, one line at a time. An internal
color counter keeps track of the color of the line to be integrated,
and takes that color’s LAMP output high when the pixel counter
reaches the value stored in that color’s LAMP On register (Con-
figuration Registers 2C-37). If the On value is greater than the
value in the Line End register, then that lamp never turns on. That
color’s LAMP output goes low when the pixel counter reaches
that color’s Off value. If the Off value is greater than the value in
the Line End register, then the pixel counter will never reach the
Off value and the lamp will always stay on. Illumination Mode 2
Illumination
Mode
Description
0
LAMP
R
, LAMP
G
, LAMP
B
outputs = 0.
This is the power-on default.
Scanning with white light:
LAMP
R
and LAMP
B
controlled by
LAMP On/Off pointers in horizontal
pixel counter (as in Mode 3),
LAMP
G
is a PWM pulse stream
Scanning with 3 LEDs in color:
LAMP
R
turns on for Red lines
LAMP
G
turns on for Green lines
LAMP
B
turns on for Blue lines
Scanning with 3 LEDs in gray:
LAMP
R
turns on for all lines
LAMP
G
turns on for all lines
LAMP
B
turns on for all lines
Figure 27:
Illumination Modes
1
2
3
Figure 28:
Illumination Mode 1
TR
LAMP
G
LAMP
R
(LAMP
R
On < Line End, LAMP
R
Off > Line End)
LAMP
B
(LAMP
B
On > Line End, LAMP
B
Off < Line End)
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相關(guān)代理商/技術(shù)參數(shù) |
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| LM9830VJD | 功能描述:視頻模擬/數(shù)字化轉(zhuǎn)換器集成電路 RoHS:否 制造商:Texas Instruments 輸入信號(hào)類型:Differential 轉(zhuǎn)換器數(shù)量:1 ADC 輸入端數(shù)量:4 轉(zhuǎn)換速率:3 Gbps 分辨率:8 bit 結(jié)構(gòu): 輸入電壓:3.3 V 接口類型:SPI 信噪比: 電壓參考: 電源電壓-最大:3.45 V 電源電壓-最小:3.15 V 最大功率耗散: 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:TCSP-48 封裝:Reel |
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| LM9830VJDX | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:LM9830 36-Bit Color Document Scanner |
| LM9831 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:LM9831 42-Bit Color, 1200dpi USB Image Scanner |
| LM9831CCVJD | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:LM9831 42-Bit Color, 1200dpi USB Image Scanner |
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