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AD9954 will not talk serial

Question asked by macduff on Jan 15, 2014
Latest reply on Jan 16, 2014 by sitti

I have been trying to communicate with the AD9954 for a few days with no success.  I am using SPI communication with clock idle low and high, driving output on idle to active state and active to idle state.  All to no avail.  I have tried writing and reading.  Reading fails in that a read of 0x1 at power up should yield three bytes, one of which is 0x18, instead they are all 0x0.  This is for a prototype board.  To eliminate other potential issues I have bypassed all circuitry and have flywired directly to the SDIO,SDO,SCLK traces.  The SYNC_CLK correctly toggles at 1/4 the oscillator frequency, but no matter what I do I cannot program the chip or read any data from it.  Is it possible I have damaged the chip?  How can I test for this?  Is there another way to test the serial communication?

 

It seems my communication setup is wrong.  SPI, Mode01, various speeds from 4 MHz to 50 kHz.

 

I would be glad to upload any schematics, etc that may be helpful.

 

Thanks!!!

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