PSoC5LP Get Seneor Capasitance API

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MiNe_85951
Level 7
Level 7
Distributor - TED (Japan)
50 likes received 500 replies posted 50 solutions authored

Hi,

We use PSoC5LP to configure the capacitive button.
Although PSoC4 has an API for acquiring sensor capacitance parameters("uint32 CapSense_GetExtCapCapacitance (uint32 extCapId)"),
It was not defined in the CSD data sheet for PSoC5LP.

Is there an API to get sensor capacitance with PSoC5LP?
Please tell us how to measure sensor capacitance with PSoC5LP.

Regards,

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BragadeeshV
Moderator
Moderator
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First question asked 1000 replies posted 750 replies posted

Hi MaMi_1205306​,

You can refer to the following code example that shows you how to measure raw counts in firmware using PSoC 1. The same algorithm can be ported to PSoC 5 as well.

https://www.cypress.com/file/138956/download

https://www.cypress.com/documentation/code-examples/capsense-controller-code-examples

I've attached a sample project that does the same in PSoC 5 device.

Note:

Substituting the values Vref,resolution(N) and switching frequency(fs) the number 100663 is obtained and the initial idac value for both the sensors is 190uA, and hence the value 190 used.

The Raw Count obtained after every scan of a sensor is divided by the uSensitivity calculated initially that gives the sensor absolute capacitance

Please let us know in case you need further help.

It is also recommended to use LCR meter to measure the capacitance of the sensor.

Regards,

Bragadeesh

Regards,
Bragadeesh

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BragadeeshV
Moderator
Moderator
Moderator
First question asked 1000 replies posted 750 replies posted

Hi MaMi_1205306​,

You can refer to the following code example that shows you how to measure raw counts in firmware using PSoC 1. The same algorithm can be ported to PSoC 5 as well.

https://www.cypress.com/file/138956/download

https://www.cypress.com/documentation/code-examples/capsense-controller-code-examples

I've attached a sample project that does the same in PSoC 5 device.

Note:

Substituting the values Vref,resolution(N) and switching frequency(fs) the number 100663 is obtained and the initial idac value for both the sensors is 190uA, and hence the value 190 used.

The Raw Count obtained after every scan of a sensor is divided by the uSensitivity calculated initially that gives the sensor absolute capacitance

Please let us know in case you need further help.

It is also recommended to use LCR meter to measure the capacitance of the sensor.

Regards,

Bragadeesh

Regards,
Bragadeesh
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