PSoC4 Capsense Sensing Frequency sweep Range

Level 3
Level 3

Hello

I Can Select Sensing Frequency 46.88Khz~ 6000KHz.

When I select certain frequency (46.88Khz~ 6000KHz)and Sense clock Source (SSC6, SSC7, SSC9, SSC10, PRS8, PRS12)

How can I Calculate sensing frequency sweep range?

ex) 3000Khz, PRS8 -> 2700Khz~ 3300Khz

because I want to  evade certain frequency range, I need to know that frequency range.

Regards,

Sunghun noh

1 Solution

Re: PSoC4 Capsense Sensing Frequency sweep Range

Moderator
Moderator

Hi suno_285741​,

1. When you are using SSC, the scan frequency (Fsw) or the Tx clock frequency is chosen as the center frequency and the spread happens to 32 different clocks evenly spaced over +/- 10% from the center frequency.  Therefore if you choose the scan clock to be 300 kHz, you can expect  32 different clocks in the range 270 kHz to 330 kHz. Note that SSC is most effective when you choose lower sense clock frequencies. Please note the conditions mentioned in the component datasheet to choose the right SSCx for your design.

2. If you are using PRS, the Fsw you set is the maximum scan frequency and clock spreads to  ModClk/ 2^PRS_N, where PRS_N is 8 or 12. Use Fsw/2 for all the calculations. (RawCounts, Cp etc)

Regards,

Regards,

Re: PSoC4 Capsense Sensing Frequency sweep Range

Moderator
Moderator

Hi suno_285741​,

1. When you are using SSC, the scan frequency (Fsw) or the Tx clock frequency is chosen as the center frequency and the spread happens to 32 different clocks evenly spaced over +/- 10% from the center frequency.  Therefore if you choose the scan clock to be 300 kHz, you can expect  32 different clocks in the range 270 kHz to 330 kHz. Note that SSC is most effective when you choose lower sense clock frequencies. Please note the conditions mentioned in the component datasheet to choose the right SSCx for your design.

2. If you are using PRS, the Fsw you set is the maximum scan frequency and clock spreads to  ModClk/ 2^PRS_N, where PRS_N is 8 or 12. Use Fsw/2 for all the calculations. (RawCounts, Cp etc)

Regards,