Runtime PLL source switching

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VlYe_281166
Level 4
Level 4
25 replies posted 10 replies posted 10 questions asked

In my project PLL drives Master_Clk.

   

I need to start the program with XTAL as PLL source  and then after some setup switch PLL to DSI or Pin signal.

   

I gues it is possible, because corresponding functions could be find in CyLib.c and PLL.c.

   

But what is the exact sequence I have to execute correctly to prevent uC hangs up during the procedure?

   

Thanks in advance,

   

Vladimir

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5 Replies
ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

These might help -

   

 

   

    

   

          

   

http://www.cypress.com/?rID=37884     AN54439

   

 

   

http://www.cypress.com/?rID=40990     AN60631

   

 

   

 

   

Regards, Dana.

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Anonymous
Not applicable

 That may be a case for Cypress support.

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ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

Also look at the clocking section of the Architecture TRM -

   

 

   

    

   

          http://www.cypress.com/?app=search&searchType=advanced&keyword=&rtID=117&id=4562

   

 

   

Regards, Dana.

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VlYe_281166
Level 4
Level 4
25 replies posted 10 replies posted 10 questions asked

 Thanks for answers,

   

yes, I saw these documents, but there are no API examples and I'm afraid there are some underwater stones. 

   

In the function comments(Cylib.c) there are mentions that PLL must be stopped before source switching. So, I wonder how to drive uC at this moment.

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ETRO_SSN583
Level 9
Level 9
250 likes received 100 sign-ins 5 likes given

This ap note shows the chain of actions necessary for controling PLL,

   

and calls out the registers for manipulation, which would be in register

   

TRM. Might shed some light on an approach you could try.

   

 

   

    

   

          

   

 http://www.cypress.com/?docID=44199     AN77900 

   

 

   

 

   

And or file a CASE to and post back to forum what you find out.

   

 

   

    

   

          

   

To file a tech case -

   

 

   

www.cypress.com

   

“Support”

   

“Technical Support”

   

“Create a MyCase”

   

 

   

Regards, Dana

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