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CFAX12864 with LED Backlighting

jpkeng

New member
Hello,

I am using the non LED backlighting version now. I would like to switch to the backlit version. What is the interface for this. Is it PWM controllred ? Or just current limited control ? Do I need to switch it with a transistor ? What is the physical connection to connect to the PCB.


Thanks,

jason
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The backlight interface is two tabs that stick down from the corners of the plastic frame, intended to go thru holes in the mounting surface. Presumably the mounting surface is your pcb, and the two holes are part of the circuit. The dimensions are shown in the data sheet for the CP1TFH, but you didn't say which display you have.

The circuit requires a current limiting resistor, I am using a 47 ohm 1/4 watt to the 5V supply (the display runs on 3.3V). I also have a FET (n-chan IRLML2803) in the cathode lead (K), that is driven by a PWM output of the micro, for brightness control. You do need to use a transistor for PWM dimming. Do you need more info?
 

jpkeng

New member
CFAX12864AP1-TFH Is ths part I am looking at using. The drawing is not very well. Is there a better drawing for the mechanics, and also which is the anode, and the cathode.

-Jason
 
I do not see a drawing for the AP1TFH that shows the backlighting tabs. The only view I can suggest is on this page:
http://www.crystalfontz.com/products/12864ap/CFAX12864AP1TFH_images.html
on the 4th image, showing the back side of the display. The tabs are visible, being separated by the width of the larger part of the FFC tail, and there are + and - markings also. I'd presume the tab dimensions are the same as the CP1TFH.

Otherwise you'll have to pester CFA support for better info.
 
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