CPU Clock, ADC Clock, Etc.

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Anonymous
Not applicable

I believe I am having troubles in setting the right Frequencies / global values for my Project. I am uprgrading to a Cypress - CY8C27443-24SXI and the Previous Chip's cpu clock ranged from 4.2MHz - 6.0MHz.

   

I am sending hi or low signals from my CY8C27443-24SXI to an analog multiplexer which I believe averaged to be roughly 2.5kHz

   

Any help with these would be appreciated, please let me know if anyone would like more info.

   

 

   

Thanks

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ETRO_SSN583
Level 9
Level 9
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Might be easier to post the project and indicate what clock rates you want

   

where.

   

 

   

    

   

          

   

“File”                                                           Designer

   

“Archive Project”

   

 

   

Regards, Dana.

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Anonymous
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 I attached my project, Currently I have been Fiddeling with the CPU_CLOCK and VC1 and VC2. If you could explain why you choose values for these when helping me that would be great.

   

Thanks,

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Anonymous
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 The Previous Attachment Was Inccorect, and I also messed with the resolution of the ADC, I normally have this at 8 Bits instead of 6

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ETRO_SSN583
Level 9
Level 9
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Normally you start with the requirements you need for each components

   

clock and then try to, using a combination of Sysclck, VC!, VC2, VC3

   

dividers to generate what you need. Its a mental trial and error exercise.

   

 

   

Normally one starts with CPU clock at fastest, in this case 24 Mhz.

   

 

   

Your A/D wants (from datasheet)

   

 

   

 

   

 

   

 

   

The max sample rate is 6.25 ksps. So compute that and probably sue VC2 to get

   

the value needed.

   

 

   

On PSOC 1 Clocks -

   

 

   

    

   

         

   

http://www.cypress.com/?rID=2773     AN32200 - Clocks and Global Resources

   

 

   

Note the clock for the ADCIN PWM wants to be the same one you use for the Analog

   

column clock.

   

 

   

 

   

Regards, Dana.

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ETRO_SSN583
Level 9
Level 9
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Some useful ref material -

   

 

   

    

   

          

   

http://www.cypress.com/?rID=2773     AN32200 - Clocks and Global Resources

   

http://www.cypress.com/?rID=2779     AN2219 - PSoC® 1 Selecting Analog Ground and Reference

   

http://www.cypress.com/?rID=2843     AN2096 - PSoC® 1 - Using the ADCINC ADC

   

http://www.cypress.com/?rID=2641     AN2239 - PSoC® 1 - Selecting The Right ADC

   

 

   

 

   

Regards, Dana.

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