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Hello,

We are working on a new desing using CY22393 programmable PLL to generates a synchronous clock from another.

We have calculated P and Q dividers and post div values and would like to check that they are compliant with your internal component constraints using your CYClocksRT software but there is no way to enter manualy que P Q and post div values in this software.

The sofware only works from enterred frequencies values, but it does not calculates the same P and Q values has we have determined and the obtained output frequency is less accurate than the one using our calculted values.

For example our input frequency is 27 * (1000 / 1001) MHz so approximatively 26,973027 MHz

We want to output a precise 9.6 MHz frequency and we have determined that it can be precisely generated using the following values :

P= 2002

Q= 225

post div = 25

Do these values match our component internal constraints ? There is no precision in the datasheet about these constraints, just a instructions to use CyClocksRT software.

But the sofware doesn't the calculated the values we want to use the obtained frequency is not as exact as what we can get.

In our example the software computes the following values :

P= 867

Q= 84

post div = 29

Frequency output = : 9,60000590 MHz frequency

Thank your for your support,

Best regards,

Corentin

I'm not sure if this is the right forum to post this question -- I've not seen much on the CY22801.  Despite reading the data sheet several times, I'm still not sure of a few things regarding programming and operation.

I see that the programmer kit CY36800 can be used for this part. One question on this programmer: does it only program the part before being soldered in circuit?  If so, I assume it has a socket for the SOIC8 part -- the photos are pretty poor quality to be able to confirm this.  Can this programmer do ISP/ICP in system programming?

OK, once the part is programmed, and I am considering a fairly simple example: 10 MHz external input, 150 MHz output on CLKA. After the part starts up, there should be the proper frequency on the output Clock A. At this point, can the frequency be changed with the use of I2C serial programming on pins 3 and 5?  It is my understanding that the original programmed output (150 MHz in this example) will come up each time the part is powered up and that the I2C programming will not, and needs to be done each time.

Now, if the previous paragraph is true, how does one use the JEDEC file to change the frequency via I2C?

Is my understanding of the programmer and the CY22801 part correct?  If not, where have I gone astray?

Thanks, Don.

Cypress is continuously improving the collateral to meet customer satisfaction. As a part of it application note: AN52133 – Frequency Margining using FleXO(TM) and Its Applications is updated as per customer’s feedback. Please review and provide your valuable feedback on the survey that will follow after the review.      

The latest copy of Application Note is available on following link:      

http://www.cypress.com/?rID=35389