Sensors中的主题 Re: MPR121 Touch detection start-up time

MPR121 Touch detection start-up time

chaitanyamuppal — Fri, 02 Jan 2015 09:35:22 GMT

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 ??

Re: MPR121 Touch detection start-up time

TomasVaverka — Tue, 06 Jan 2015 10:33:47 GMT

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.

Re: MPR121 Touch detection start-up time

chaitanyamuppal — Wed, 07 Jan 2015 06:41:39 GMT

Hi Tomas,

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

thanks,

chaitanya.