MPR121 Startup

[zachdevries]

Hello,

I am using the MPR121 chip to control 8 capacitive buttons. If I press any one of these buttons while the initialization is in progress, the chip no longer responds to interaction.

If I ensure nothing is in contact with the touch buttons during initialization, all of the buttons work properly.  I have tested this on 16 units, and all of them react the same. 

I followed the source code outline on Sparkfun's website for my initialization procedure. I also looked through the available application documents provided, but did not see anything relating to this issue.  Has anyone else encountered this problem and if so, was a solution found?

Thank you in advance for any help provided.

[david_diaz]

Hello Zach,

Could you please be more specific about the issue mentioned?

After you touch one of the electrodes while the initialization process, the device stops working?

Please review the MPR121 Design Guidelines attached to this response.

I recommend to compare your initialization procedure with the design guidelines mentioned above.

I assume the touch pad baseline filter is not set correctly.

By the way, I made some tests using the KITMPR121EVM and it works properly.

Have a great day.

David