FEASA LED ANALYSER
ICT VERSION
In-Circuit Test Mode
In-Circuit Test Frequency Mode
This mode is the easiest to implement at In-Circuit Test provided a method is available to
measure the output frequencies. The frequencies range from 1KHz to 100KHz and the output
is a square wave signal with a voltage swing from 0V to 3V.
The following sequence must be used to test the LED's successfully:-
Setup: Using Terminal Window and Serial port on the Led Analyser, Set the relevant Frequency
mode, HSI or WSI or xyI
1/
Turn on the LED's to be tested.
2/
Apply power to the LED Analyser.
3/
Initialize the Analyser.
4/
Capture the LED Data.
5/
Read and Test the Hue (colour) or Dominant Wavelength or x Chromaticity Frequency.
6/
Read and Test the Saturation or y Chromaticity Frequency.
7/
Read and Test the Intensity Frequency.
The Analyser will measure the data from all the LED's in one capture operation. However, the
data for each LED is read out one at the time. The data from last capture is stored in the
Analyser until a new capture is done or power is removed.
Each Fiber or LED has an Address associated with it. Since there can be up to 20 LED's to be
tested - Hexadecimal Addresses 0x01 – 0x14 are used to access the data for each individual
LED. LED1 will have address 0x01, LED2 will have address 0x02, LED10 will have address
0x0A and LED20 will have address 0x14 etc.
Since the Analyser can test LED's that are dim to very bright - the correct intensity range
should be used. There are five ranges available –
Low, Medium, High, Super
and
Ultra
. The
low range is for dim LED's and the ultra is used for the very bright LED's. There is also an
auto
range and should only be used when both dim and bright LED's must be tested together.
PWM Leds are captured in the same manner except pin 8 is driven Low.
For Very Bright Leds the Feasa x-IB High Brightness Analyser is recommended.
Figure 12 shows all the addresses that can be input to the LED Analyser and the function of
each address.
These functions will be explained in the following sections.
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