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ADF7021 CLKOUT signal in SPI mode

Question asked by andres on May 29, 2011
Latest reply on Jun 10, 2011 by enash



I'm having some troubles with ADF7021 connected to MSP430F2418 via SPI bus.

As far as I know if SPI is used REGISTER0 DB28 must be set to 1 and REGISTER15 DB17-DB19 must be set to 0x07, is this correct?

Is it true that microcontroller SPI must be used as slave with SPI mode 3?


And what about CLKOUT pin - if i have programmed registers R0 and R15 then after that there should be clock signal generated by ADF7021 on CLKOUT?

Could you tell me what is the signal frequency of CLKOUT?


For some reason I don't see any clock signal on CLKOUT, I'm using 10 MHz oscillator with the ADF7021.




Datasheet page 22: says that CLKOUT divider is set in REGISTER1 DB7-DB10

If this divider is set to 0 then CLKOUT is disabled despite the fact that I have enabled SPI with register 0 and 15 - is this correct?


EDIT2: Yup - it is correct. If I set divider to 4 in REGISTER1 DB7-DB10 then I can see clock signal on CLKOUT pin.

Message was edited by: andres