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Mater Clock and the internal clock of a peripheral- should they both be of same freq?

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Newbie level 6
Jul 8, 2011
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Hi there,

I am using an SPI interface to comunicate between Microcontroller( e.gPIC18452) and an audio codec IC.I have a little confusion in understanding the clocks.Here is what i know:
Since the microcontroller will act as MASTER, its clock will be used in transferring and receiving digital data from the IC.
But the IC is also clocked by an internal crystal (12.288 MHz)..Will this clock will be ruled out and NOT used for any internal process of the peripheral ?
OR the SPI serial Clock is just used in transferring data serially and the rest of the processing like register interfacing etc. in the IC is carried out by the internal clock(12.288MHz)?
Also , will I have to use the same frequency clocks for both the Controller and the audio IC for syncronization(like I shall provide SCLCK of 12.288 MHz) or the clock frequencies can be different ?

Thank you in advance!

You don't have to worry about the clocks.
The Master clock is used to clock the data from the master into the slave and back again, it does not have anything to do with the Slaves internal clock. It is just used to synchronize the data transfer.
thanks@btbass-- what if my Master Clock is quite faster than the peripheral clock?it will transmit data at a faster rate than the processing of the peripheral IC , and there might be loss of information ...
and i accidently posted this thread here (since it was my first one )-- how do i move it to the microcontroller forum? (since that is more aproppriate )

You need to check the data sheet of the IC. There must be some information on the recommended SPI interface clock speed so you have no loss of data?

Not sure how you move the thread.
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