Why is the SmartSense (Full Auto-Tune) limited to 45 pF of sensor capacitance that can be supported?

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
NaMo_1534561
Level 5
Level 5
Distributor - Macnica (Japan)
100 replies posted 100 sign-ins 50 replies posted

Hello,

Why is the SmartSense (Full Auto-Tune) limited to 45pF of sensor capacitance that can be supported?

I refer the PsoC4/PsoC6 Capsense design guide as below.

PSoC® 4, PSoC 6 MCU CapSense® Design Guide, Doc. No. 001-85951 Rev. *U

5.3 Manual Tuning

https://www.cypress.com/file/46081/download

0 Likes
1 Solution
Hari
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hello

For a parasitic capacitance value of 100pF, smartsense will not be able to tune. Manual tuning is the reliable and better option.

However, to save time, you can first set the sensor to smartsense and check the values such as sense clock frequency, scan resolution and modulator IDAC. These values can be applied in the manual tuning setting in order to tune the sensor.

Do let us know in case of any other query.

Thanks and regards

Harigovind

View solution in original post

0 Likes
3 Replies
Hari
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hi

Could you please let us know why you require this information? We would like to know if there is any specific use case where this information is necessary.

Thanks and regards

Harigovind

0 Likes
NaMo_1534561
Level 5
Level 5
Distributor - Macnica (Japan)
100 replies posted 100 sign-ins 50 replies posted

Hello Harigovind-san,

That is just a technical question.

The fourth generation CapSense supports up to 5pF-200pF range, but the adjustable range with SmartSense Auto-tuning remains at 45pF. Is this because there is a limitation in the range of parameters to be adjusted by SmartSense Auto-tuning?

The target for the customer sensor parasitic capacitance value is 100pF.

If CapSense can tune a 100pF sensor with SmartSense Auto-tuning, customer can significantly reduce the sensor tuning time.

However, since it is impossible now, it corresponds by manual tuning.

Best Regards,

Naoaki Morimoto

0 Likes
Hari
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hello

For a parasitic capacitance value of 100pF, smartsense will not be able to tune. Manual tuning is the reliable and better option.

However, to save time, you can first set the sensor to smartsense and check the values such as sense clock frequency, scan resolution and modulator IDAC. These values can be applied in the manual tuning setting in order to tune the sensor.

Do let us know in case of any other query.

Thanks and regards

Harigovind

0 Likes