topic Factors that can affect TSI0_GENCS in Kinetis Microcontrollers

Factors that can affect TSI0_GENCS

javervalino — Wed, 09 Sep 2015 05:28:37 GMT

I just want to ask your expertise regarding our current issue in touch responsiveness.

Our products are now in mass production, but recently we are having an issue in touch responsiveness; there is some sort of delay in touch and sometimes it is very hard to press.

In line with this we did some investigation in hardware and software.

Upon checking the TSi0_GENCS register, bad units has different register from the other units.

For all units with good touchpad response we are getting TSI0_GENS “0x10c5c7c8”

And for all the units with bad response we are getting TSI0_GENS “0x10c487c8” or “0x10c4a7c8”

What I did in software is that I strip all the code and just left the code below and the same issue occurs.

I only retain the basic call for TSI as generated by Processor Expert.

Based on my previous experience if I have same hardware TSI0_GENCS supposed not to change since we are using same code for all the units.

Attached is the stripped sourcecode for your reference.

Can you sight some factors that can affect TSI0_GENCS for example in hardware, mechanical or even software?

Re: Factors that can affect TSI0_GENCS

vicentegomez — Mon, 14 Sep 2015 17:34:46 GMT

Hi Javer

I believe that this is the same problem that I am working with Marco A.

I believe that the problem is that the base line is increasing with the time, due the function of the electrode and the water.

I recommend that you perform hardware calibration after some time like 5 min without activity.

Checking your data the threshold (TSIx_TSHD) is different on the good and the failed part.

I hope this will help you.

Regards

Vicente Gomez

Re: Factors that can affect TSI0_GENCS

javervalino — Wed, 16 Sep 2015 03:00:33 GMT

Hello Vicente,

How is the progress of your work?

What do you mean by "due the function of the electrode and the water" ?

>>I recommend that you perform hardware calibration after some time like 5 min without activity.

This cannot be done in our application, since the user must use the device touch after powering it up.

>>Checking your data the threshold (TSIx_TSHD) is different on the good and the failed part.
Yes, its keep on happening even we use the code above. I just want to know why its not happening on other unit?

Almost 80% in our production are good and the other part is experiencing this phenomena. Right now we are thinking that this is a problem on the MCU. What do you think?

Best Regards,

Javer Valino

Re: Factors that can affect TSI0_GENCS

vicentegomez — Thu, 17 Sep 2015 17:02:19 GMT

Hi Javer

What do you mean by "due the function of the electrode and the water" ?, I am thinking that when the water keeps long time on the electrode, it start to get some change producing that the base line will increase, after some time it does not response. But if you have 80 % working, I believe that this is not the cause.

What happens if you change the board, I mean on one unit that failed change the hardware (the board with the KL05) and keep the same electrode, and put a unit that works properly and check, also put the failed board on a good electrode.

After that you can check if the problems follows the board or the electrode.

After you can change the MCU and check if the problem follow the MCU or follow the board.

Please let me know the result, if the information is confidential, we can use an SR (service request) for that.

Regards

Vicente