CAT3649AGEVB
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4
Graphical User Interface (GUI)
After connecting the CAT3649 EVAL board to the PC via
USB cable, the user can run the program
CAT3649EVAL.exe.
If the program is started without the USB connection, the
following message is displayed:
“The CAT3649EVAL
Board is not detected!”.
The CAT3649 operating mode is selected by pressing one
of the “check” buttons “PWM” or “ADIM”.
PWM Operation Mode
At start
−
up, on the GUI is selected, automatically, the
PWM mode of operation (as shown on Figure 4).
In this mode, the user can increase/decrease the LEDs
intensity by moving the potentiometer cursor or by pressing
the keys “
−
>” and “<
−
” on the keyboard after selection of the
potentiometer.
Now, in the frame “CAT3649 Command Mode”, the
PWM Timing Diagram for a frequency of 300 Hz is
displayed. The period of a pulse (3.3 ms) is the sum between
“Ton” and “Toff”.
ADIM Operation Mode
After pressing the “ADIM” button, the “ADIM” frame
becomes enabled (Figure 5). In the “CAT3649 Command
Mode” frame, the Timing Diagram is only a line that
represents the low level on the ADIM input.
If the “EN/DIS” button is pressed, the device will be
enabled. The red LEDs on the GUI and on the board will light.
The Timing Diagram represents, now, the high level on
the ADIM input. (Figure 6).
At this moment, the LEDs intensity is at full scale.
If the “DIM” button is pressed for a short time a single
pulse is applied to the “ADIM” input of the device.
If the “DIM” button is pressed continuously, at every 0.4
seconds, a pulse is applied to the device. (Figure 7).
If the “EN/DIS” button is pressed again, the device will be
disabled. The red LEDs on the GUI and on the board will be
off.
At this moment, on the ADIM input is at the low level.
(Figure 8).
The LEDs intensity is zero.
Ambient Light Sensor NOA1211 Operation Mode
The Ambient Light Sensor NOA1211 can command the
LEDs intensity using the microcontroller and the CAT3649.
If the option button “Select” of the frame of the Ambient
Light Sensor is pressed while in PWM mode, the “Gain”
frame will be enabled.
In this frame only the “Power Down” option is selected,
because the “Ambient Light Sensor”, at this moment, is off.
(Figure 9).
The user can select one of the options “Medium” or “Low”
corresponding at the LED’s intensity level domain.
(Figure 10). Depending of the light’s intensity exposed to
the sensor, the LEDs will light proportionally.
Operating mechanism is as follows:
The sensor outputs a current proportional to the ambient
light. This current is converted to an output voltage by
resistor R6. The output voltage is applied to the input of the
10
−
bit ADC (Analog to Digital Convertor) from the
microcontroller.
The microcontroller converts the digital value, received
from ADC, into a PWM signal applied to the CAT3649 LED
Driver.
CAT3649 controls the six LEDs’ intensity.
Status Box
This box displays various messages about the application
status.
Figure 4. GUI – PWM Mode
