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CFAG320240CX-TFH-T-TS with 3.3 V I/O

vitomsc

New member
Hello,

I have purchased a 320x240 LCD (part number CFAG320240CX-TFH-T-TS). How can I configure the jumpers in back side printed circuit board of this module to use 3.3 V input/output voltage levels?

Thank you for your help.

Victor
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CF Tech

Administrator
It is not trivial to operate the CFAG320240CX-TFH-T-TS at 3.3v.

There are three challenges:

1) Create Vo (pin 3) (~ negative 20.5v) so that Vlcd (23.8v) is met. This typically requires a negative voltage generator. There is a negative voltage generator on the CFAG320240CX-TFH-T-TS, but it is designed to use +5v as its input, not +3.3v, so it may not be adequate.

2) Supply current to the LCD. This supply must be current limited. The forward voltage of the LEDs are 3.5v. Probably this will require a step-up supply. Perhaps something like this:

http://focus.ti.com/docs/prod/folders/print/tps61058.html

3) Operate the S1D13700 at 3.3v. The S1D13700 is characterized at 3.3v (even though the CFAG320240CX-TFH-T-TS is only characterized at 5v). You would need to use the S1D13700 information from its 3.3v sections instead of the CFAG320240CX-TFH-T-TS data sheet.

http://www.crystalfontz.com/products/320240cx/S1D13700F01.pdf
 

KMEndre

New member
Hi!

I use this display at 3.3 V, because my microcontroller (MSP430F1612) works at that voltage.

You must only set the "VR1" trimmer in back side circuit board (counter-clockwise). But carefully!
VLCD = (VDD - VO) = 23.8v
So your VDD is 3.3V, Vo (at PIN 3) should be set to approx -20.5 V.
My trimmer is at 10'o clock.

Sorry for my poor english

K.M. Endre




Hello,

I have purchased a 320x240 LCD (part number CFAG320240CX-TFH-T-TS). How can I configure the jumpers in back side printed circuit board of this module to use 3.3 V input/output voltage levels?

Thank you for your help.

Victor
 
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