questions about CY3280-BK1

[befic_2639911]

Hi,everyone.

     I have some questions about Cy3280-BK1,which contains CY3280-20x34 and CY3280-21x34 Universal CapSense Controller boards.

     Now I use bridge control panel to read touch data from CY3280-21x34 board and display them. but data and chart are totally different from expectation.

     In the following chart and table,raw counts  sharply reduce from 62730 to 10 instead of increasing when finger touchs the sensor.And the touch data is 10 ,stays the same . why does it work in this way?

     According to CSD theory, Cf+Cp will lead to an bigger raw counts.

     Question2: CY3280-20x34 uses CSA while CY3280-21x34 uses CSD. which one  is better,CSD or CSA ? what are the advantages and disadvantages of each?

   

[ShanmathiN_06]

Hi,

1) I'm unsure why the raw counts and baseline are not the same, when the sensor is not touched. Also, sensor status seems incorrect.

Could you please change to linear plot and send the wave forms and table, when there is no touch present on the sensor?

Ideally, position must be 0, status must be 0 and, raw counts and baseline should almost be the same.

If these are correct, then we can proceed to touching the sensor and observing the raw count change. BTW, yes you are right, increase in Cf should increase the raw counts.

2) You could refer to CapSense Device and Method Selection Guide.

In general, if you would like touch-sensing, Cypress recommends you to look at the newer generation CapSense devices (MBR3xxx, PSOC: 4000S, 4100S, 4100S PLUS series)

Pls refer to https://www.cypress.com/file/41076/download

Thanks,
Shanmathi

[befic_2639911]

Hi,ShanmathiN_06,thank you very much.

    I did all steps again and again according to CY3280-BK1_User Guide.pdf.

    Now I get new data as below. It is different with previous post result. Last time,i did it just as the user guide too.

     Just as you said, when no touch ,raw count is almost as same as baseline, and touching leads to a bigger raw count.

   but It is weired that almost 170 cnts,rawcount will drop to around 30.

     is it related to firmware version? Programmer mentioned "out of date".

BTW, CapSense Device and Method Selection Guide is out of link.

  

[ShanmathiN_06 · Accepted solution]

Hi,

Q1) is it related to firmware version? Programmer mentioned "out of date".

It is recommended to update to the latest version. However, it would not resolve the issue you are facing.

Q2) CapSense Device and Method Selection Guide is out of link.

What do you mean by "out of link"? The device and the application notes related to the device are obsolete. But, I found teh guide in slideshare and hence shared the link.

Q3) It is weired that almost 170 cnts,rawcount will drop to around 30.

From the two tables that you had shared, it looks it is an I2C communication issue. Note that whenever raw counts decrease rapidly, the sensor index value has changed.

First step would be to check the .iic file. Please double check if the sensor index you write is same as the one reported in the table. You could also share your .iic file. If they are not the same, you could simply discard the corrupted data (i.e) data received during a sensor_index mismatch.

Thanks,
Shanmathi