MPR121 Touch detection start-up time

[chaitanyamuppal]

HI,

I am using MPR121 touch controller. It is taking  10 seconds time to detect touch, while GPIO control is happening immediate after power on.  I din't see anywhere in datasheet about start up time for MPR121 to detect touch.

Is there possibility to reduce this 10 seconds time by changing some config ??

[TomasVaverka · Accepted solution]

Hi Chaitanya,

This initial delay is caused by a large time constant of the baseline tracking filtering system. To reduce it, set both the CL (0x5E register) and BVA (0x7B register) bits to 0b10 or 0b11.

I hope it helps.

Regards,

Tomas

PS: If my answer helps to solve your question, please mark it as "Correct" or “Helpful”. Thank you.

[chaitanyamuppal]

Hi Tomas,

Now start-up time reduced to 4 sec by using above config. Thanks for your reply.

thanks,

chaitanya.