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PSoC 4 MCU

YuMa_1534086
Contributor

Hello Cypress.

Q1)

Why does not CSX have PRS setting?

Is there any reason why CSX can not drive at PRS?

Q2)

Does CSX have flat spots issue same as CSD?

Q3)

If Q2 is yes, where is the point where flat spots issue occurs?

Are they the same as CSD? So 25%, 50% and 75% of CSX max RawCount?

And how should CSX avoid flat spots issue?

CSX does not have PRS.

Best Regards.

Yutaka Matsubara

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1 Solution
RyanZhao
Moderator
Moderator

Matsubara-san,

A1) PRS may have large noise and low SNR for CSX

Q2) Yes. With larger CintA/B than our recommendation, the flat spots will be more obvious. With the recommended CintA/B, the flat spot may not be observed obviously.

Q3) Yes. 25%, 50% and 75% of CSX max RawCount.

SSC can help to avoid Flat Spots same with PRS.

Best Regards,

Ryan

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6 Replies
RyanZhao
Moderator
Moderator

Matsubara-san,

A1) PRS may have large noise and low SNR for CSX

Q2) Yes. With larger CintA/B than our recommendation, the flat spots will be more obvious. With the recommended CintA/B, the flat spot may not be observed obviously.

Q3) Yes. 25%, 50% and 75% of CSX max RawCount.

SSC can help to avoid Flat Spots same with PRS.

Best Regards,

Ryan

View solution in original post

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YuMa_1534086
Contributor

Ryan-san.

Thank you for your response.

Below is design guide description about flat spots.

pastedImage_0.png

According this description, it seems that only way to avoid flat spots is to use PRS.

Because design guide describes only PRS.(There is no SSC)

But you said that SSC can help to avoid Flat Spots same with PRS.

In actual, is SSC also useful for avoiding flat spots same as PRS?

If yes, which of PRS and SSC is better in order to avoid flat spots?

Best Regards.

Yutaka Matsubara

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RyanZhao
Moderator
Moderator

Matsubara-san,

Sorry sincerely again for the late reply.

Either SSC and PRS can avoid flat spots. Flat spot will happen under direct clock mode. To resolve the problem, spreading a clock can be used. SSC is a spectrum spreading clock, can also make sense for avoiding flat spot same with PRS.

Thanks,

Ryan

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YuMa_1534086
Contributor

Ryan-san.

Which of PRS and SSC is better in order to avoid flat spots?

Or is there no significant difference as solution of flat spots?

Best Regards.

Yutaka Matsubara

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RyanZhao
Moderator
Moderator

Matsubara-san,

There is no significant difference as solution of flat spots.

Best Regards,

Ryan

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YuMa_1534086
Contributor

Ryan-san.

Thank you for your response.

I understand it.

Best Regards.

Yutaka Matsubara

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