issue while working on MPR121EVm

[ravindhar]

Hi, I am using KITMPR121EVM kit to evaluate one of our proximity capacitor touch unit. Below is my set up:

I have powered EVM over USB  and connected 6-electrode pad on it it, having MPR121. Sensor tool box detects module and am able to do demo and evaluation of 6 pad electrode.  

Now, I removed MPR 121 and connected I2C lines ( SDA , SCLK, IRQ , VDD and GND ) to my target unit. Here also sensor tool box able to detect my board as 6 pad electrode and am able to enter into eval mode. However, the touch on my board doesn't reflect on display. I confirmed that my unit is working one. 

I have attached two docs for your reference one working with freescale tool kit and one with my unit. below is how I connected lines on

     JP1-> IRQ

    JP2->SLCK

    JP3->SDA

    JP4->GND

    JP5->VDD

Thanks, Ravi

[TomasVaverka]

Hi Ravi,

I am unable to find the two docs you are referring to, could you try to attach them once again, please?

Right now, I cannot say where the problem might be.

Regards,

Tomas

[ravindhar]

Hi,

Schematics of target Unit.

Regards

Ravi.

From: Reddy, Ravindhar

Sent: Tuesday, July 22, 2014 8:08 AM

To: 'jive-1247560643-4usc-2-91cj@freescale.hosted.jivesoftware.com'

Subject: RE: - issue while working on MPR121EVm

Hi Tomas,

PFA two documents which I attached earlier.

Thanks

Ravi

[TomasVaverka]

Hi Ravi,

I am still not sure why it is happening.

Do the registers change their value? If so, then the I2C communication and power connection should be OK.

Try to set with registers in the tables, for example the threshold, the charge current and then see the response.

Regards,

Tomas

[ravindhar]

Hi,

I did supply 2.6V on VDD of target unit separately and connected power supply GND and VSS/GND of target unit to pin2 of J1 connector on EVM. I was successful to get the response for touch .However, the connection goes for toss intermittently. I need to disconnect the EVM from laptop and restart tool for test again.

Thanks

Ravi

[ravindhar]

Hi Tomas,

PFA two documents which I attached earlier.

Thanks

Ravi