TSC2007: It points wrong spot when I touch the screen.

ok please send me thee schematic

Dear Sanjay,

Thank you for your support. I attach a schematic in PNG file below.

Was there any customer who had a similar issue?

Best regards,

Chase

To a first look the schematic looks fine.

Unfortunately Our firewall does not allow me to see the video. Can you please elaborate in words the exact issue

that you see. I will then try to guide you

Dear Sanjay,

Thank you for your support.

Could you check that you can download the video below?

You can see it after 10 seconds of this video.

Best regards,

Chase

i saw the video . It looks as if if a touch is detected anywhere on the right of the screen.

As a first step i would suggest to disconnect the transient suppressors on the 4 pins and to recheck behaviour.

As a second step i would suggest to send the command to measure X position. This makes X+ 3.3V ,X- 0V and Y+ is fed to the ADC.

They should put an CRO on X+,X- and Y+. When x+ is 3.3v,X- =0 y+ is a DC Level that goes from 0v to 3.3v as we move finger from left to right.

They should check this on a CRO

Dear Sanjay,

Thank you for your support. I will ask my customer to try what you said.

1. Does CRO mean oscilloscope?

2. If I send a command 1100, X+ is 3.3V and X- is 0V (these 2 are static value) and Y+ would be move from 0V to 3.3V as I "drag" a screen from left edge left to the edge right. Do I understand correctly?

But  why the X values are static and Y value is changing? cause it is called "Measure X position" on the table.

and second, What should I do if the result is different from you guided?

Best regards,

Chase

Yes CRO is actually an obsolete term for an oscilloscope. Sorry about that..

I would say that to begin just use the customers code and put the scope on the 3 points as i mention. Actually the IC gives a 3.3v across the X+ and X-points . When customer moves finger acoss x he is actually creating a tap of a potentiometer from the x+ to x-line. . Therefore if we look on Y+line we see a voltage that does from 0 to 3 v as customer moves finger from left to right.

Alternatively customer should also be able to read the actual x and y coordinates as we move finger from left to right and top to bottom.

You can ask him to tell you the x value as you move from left to right. it should smoothly change from minimum to maximum. if this is so our chip is fine and there is some other issue with customer software 

Dear Sanjay,

Thank you for your support.

first of all they removed all transient suppressors -> same error / change ferrite bead to 0 ohm resistor -> same error.

I asked about measurement using oscilloscope.

and I have one more question, Are there any tools about calibration?

I think every device which use resistive touch should have calibration program, cause it sometimes happens when we have to re-calculate it. 

or should we make it ourselves?

Best regards,

Chase

Since the customer already has made firmware he would have the X and Data as we touch from left to write of screen. For 12 bit resolution values of 0-4096

should be possible. First thing is to verify if the X value he is seeing is moving linearly from 0 to 4096 as finger moves from left to right