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AD9951 not responding

Question asked by Flanbix on Jun 15, 2011
Latest reply on May 20, 2013 by MohitH

Hi,

 

Have done a board with an AD9951. But I cannot get the DDS to respond my SPI commands. The output of the DAC stay flat or the SYNC_CLK stay at the crystal frequency/4.

 

Here is an exemple of how I write the CFR2 and a picture of the SCK and SDIO:

 

// Reference Clock
CS=0;
WriteSPI(0b00000001);    // Write instruction of the register 0x01
WriteSPI(0b00000000);    // Write data starting from MSB
WriteSPI(0b00000010);    // Crystal OUT pin active
WriteSPI(0b00100000);    // 4x Multiplication
CS=1;
LATCbits.LATC0=1;         // I/O Update
Delay100TCYx(1);
LATCbits.LATC0=0;

 

Any clue?

 

Thanks.

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