JAI CB-140GE, Руководство пользователя

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CM-140 GE / -RA/-UV / CB-140GE/-RA
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Start Point
End Point
Length
Start Point
End Point
Length
6.1.2. 12-bit Counter
A 25MHz clock or the camera pixel clock (65MHz for CM-140GE/CB-140GE and 33.75MHz for CM-
140GE-UV)) can be used as a source. The counter has a “Divide by N”, where N has the range 1
through 4096, allowing a wide range of clock frequencies to be programmed. Setting Value 0 is
bypass, setting value 1 is 1/2 dividing and setting value 4095 is 1/4096 dividing.
6.1.3. Pulse Generators (0 to 3)
Each pulse generator consists of a 20-bit counter. The behavior of these signals is defined by their
pulse width, start point, end point and number of repetitions.
The pulse generator signals can be set in either triggered or periodic mode.
In triggered mode, the pulse is triggered by the rising edge/falling edge/high level or low level of
the input signal.
In periodic mode, the trigger continuously generates a signal that is based on the configured pulse
width, starting point and end point.
Fig.7 Generated pulse
Setting example:
The following example shows the FVAL input to pulse generator. The pulse generator creates the
pulse using FVAL and the pulse is output through GPIO PORT 1. The pixel clock is 60MHz.
Pulse Generator 0 IN
(FVAL )
0 1 2 3
1
99 100 101 102 103
2 1
Start Point = 0 End Point = 99
Length = 102
Clock IN
Clock Source=Pixel Clock ( 60MHz)
Clock Pre-scaler = 2399
⇒
25KHz
1/25KHz = 40µs
Pulse Generator Clear = 4: Rising Edge
Pulse Generator 0 OUT
(GPIO Port 1 )
Repeat counter: 0 to 255
=0: Continuously repeated
Pulse Generator Setting Example
Fig 8. Pulse generator setting example
The created pulse rises up at the start point and falls down at the end point as shown above.
Accordingly, the High duration is (End point – Start point) clocks x (1/ Pulse gen. frequency).
In the above example, the original oscillation uses pixel clock (60 MHz) and the pixel clock is
divided by 2400. A pulse frequency of the generator is 25 KHz ( 60000000/2400). As the start point
is 0 and the end point is 99, the pulse having 100 x 1/25000 = 4ms width is created.