How could I know sense clock frequency and the current Icomp/Imod?

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user_4653071
Level 3
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25 replies posted 10 replies posted 5 replies posted

I am making the “proximity” project  with the PSoC CYCKIT040and  shield CYC024, and I want to know the capacitance by the formula. But I get trouble with sense clock frequency Fsw and the current Icomp/Imod, could anyone help me ?thanks.

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LinglingG_46
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500 solutions authored 1000 replies posted 10 questions asked

1: Change the CSD tuning mode from "SmartSense" to "Manual tuning"

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2: Uncheck the Enable IDAC auto-calibration.

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3: You can get the Gain IDAC here.

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4: Then you can get all the parameters in the formula.

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the module in this example proximity project is Capsense CSD,not Capsense;just like this,

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in this mode,the sense clock divider  is 2,and then i wanna know whether the sense clock frequency equals HFCLK/2 ?

in addition,how can i get the IDAC gain in this mode?i cant find the item ‘widget hardware Paraments'.

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in this mode,the sense clock divider  is 2,and then i wanna know whether the sense clock frequency equals HFCLK/2 ?

No.

We assume that the project name you refer to is "proximity"_ Distance_ 040 "in this project, the mode of adjustment is Manual, which enables auto-calibration function, and the induction clock frequency Fsw is set up by component parameters. The value of modulation IDAC and compensation IDAC is calculated on the basis of algorithm. The CapSense component is set. The sense clock divider of proximity sensor is 2, the mode is PRS auto, and the system clock hfclk frequency is 12Mhz. According to the figure below, the calculated value of FSW is:

Fsw = (HFCLK/ASD)/4 = (12MHz/2)/4 = 1.5MHz

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in addition,how can i get the IDAC gain in this mode?i cant find the item ‘widget hardware Paraments'.

If you choose the 4X in advanced tab, the IDAC gain is 1.2uA.

The values of modulated and compensated IDAC are calculated by the system, so there is no way to know the specific value, which can only be read by code after the chip is powered on. You can declare the following two arrays in main. c, and then read out the two IDAC values of proximity sensor directly.

If you have not modified the project, the array element ID of proximity sensor should be 0,

so CapSense_ Modulationidac [0] and CapSense_ Compensation IDAC [0] stores two IDAC calculated values of proximity sensor. Let's assume that both values are 5, then the actual IMOD = 5 * 1200na = 6ua, and Icomp = 5 * 1200na = 6ua

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thank u so much.

another problem: how can i get the compensation and modulation IDAC value in this mode? are they both equal to 12?if not,what should  i do?

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the module in this example proximity project is Capsense CSD,not Capsense;just like this,

in this mode,the sense clock divider  is 2,and then i wanna know whether the sense clock frequency equals HFCLK/2 ?

in addition,how can i get the IDAC gain in this mode?i cant find the item ‘widget hardware Paraments'.

0 Likes