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PSoC™ 4

wangyuanfan
Level 3
10 replies posted 10 questions asked 10 sign-ins
Level 3

let me ask you a basic question.

I would like to know the definition of "baseline".

In addition, I would like to know what kind of difference in behavior occurs if I check or uncheck the param 'Enable sensor auto-reset' in Configure CapSense . To do this, I think I first need to know what a Baseline is.

Thank you.

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

Hi @wangyuanfan 

 

Baseline: The raw count value of a sensor may vary gradually due to changes in the environment such as temperature and humidity. Therefore, the raw count is low-pass filtered to create a new count value known as
the baseline that keeps track of and compensates for the gradual changes in the raw count. The baseline is less sensitive to sudden changes in the raw count caused by a touch. Therefore, the baseline value provides the reference level for computing the signals

Hari_0-1638518108911.png

 

 

Enable Sensor Auto Reset : When enabled, the baseline is always updated. When disabled, the baseline is updated only when the difference between the baseline and raw count is less than the noise threshold.
When enabled, this feature prevents sensors from permanently turning on when the raw count accidentally rises due to a large power supply voltage fluctuation or other spurious conditions.

Because the baseline is always updated when sensor auto reset is enabled, this setting limits the maximum time
duration for which the sensor will be reported as pressed. However, enabling this parameter prevents the sensors from permanently turning on if the raw count suddenly rises without anything touching the sensor. This sudden rise can be caused by a large power supply voltage fluctuation, a high-energy RF noise source, or a very quick temperature change.

Hari_1-1638518128122.png

 

 

Please refer to CapSense design guide - https://www.cypress.com/file/46081/download for more details. 

 

Best regards, 
Hari

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2 Replies
Hari
Moderator
Moderator 750 replies posted 500 replies posted 250 solutions authored
Moderator

Hi @wangyuanfan 

 

Baseline: The raw count value of a sensor may vary gradually due to changes in the environment such as temperature and humidity. Therefore, the raw count is low-pass filtered to create a new count value known as
the baseline that keeps track of and compensates for the gradual changes in the raw count. The baseline is less sensitive to sudden changes in the raw count caused by a touch. Therefore, the baseline value provides the reference level for computing the signals

Hari_0-1638518108911.png

 

 

Enable Sensor Auto Reset : When enabled, the baseline is always updated. When disabled, the baseline is updated only when the difference between the baseline and raw count is less than the noise threshold.
When enabled, this feature prevents sensors from permanently turning on when the raw count accidentally rises due to a large power supply voltage fluctuation or other spurious conditions.

Because the baseline is always updated when sensor auto reset is enabled, this setting limits the maximum time
duration for which the sensor will be reported as pressed. However, enabling this parameter prevents the sensors from permanently turning on if the raw count suddenly rises without anything touching the sensor. This sudden rise can be caused by a large power supply voltage fluctuation, a high-energy RF noise source, or a very quick temperature change.

Hari_1-1638518128122.png

 

 

Please refer to CapSense design guide - https://www.cypress.com/file/46081/download for more details. 

 

Best regards, 
Hari

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wangyuanfan
Level 3
10 replies posted 10 questions asked 10 sign-ins
Level 3

I got it ! Thank you so much.

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