external clock for PSOC4

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Anonymous
Not applicable

I need to using an external crystal for better performance (40MHz TCXO).

   

So I connect this with P5(1). 

   

Configure all the clock using external clock.

   

But the system can't boot up.

   

Any special setting needed?

   

Please check the attached for clock setting.

   

BTW: The crystal is 40MHz. Is this must be 48MHz/24MHz?

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Bob_Marlowe
Level 10
Level 10
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P5_1 is for input of an external oscillator, not only a crystal. I think this is just a naming difference, is it?

   

When you did not additionally provide the 24MHz crystal your system will not run in this configuration.

   

What is the exact device number you're using?

   

 

   

Bob

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Anonymous
Not applicable

CY8C4247LQ-BL483  and CY8C4248LQ-BL583

   

There 24MHz onboard, and running well using this 24MHz.

   

Yes, it is a TCXO with VDD 1ppm oscillator.

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Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

I would try to boot using IMO and then switch to external clock with CySysClkWriteHfclkDirect() API (see "System Reference Guide")

   

 

   

Bob

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Anonymous
Not applicable

Thanks, after using this method it works.

   

And in the system reference guide, it said PSOC4 can't boot with external clk, I just didn't notice this.

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