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ad9957 dac Interpolation mode does not work

Question asked by abc2005211 on Nov 21, 2016
Latest reply on Jan 3, 2017 by KennyG

I use the ad9957 evaluation board and successfully applied single tone mode and qduc mode of ad9957.

But when i evaluated ad9957  dac interpolation mode , it did not work.

My operation order was below:

1. write cfr1  16'h0200_0000 

2. write cfr2  16'h0040_0a20

3. write cfr3 16'h1d3f_4150

 

4. write 0x0e reg   64'h08b5_0000_0000_0000

 

5. set tx enable high  with connect it to vcc.

 

6. set D0-d17  high or low with connect one of the to the vcc .

 

i watched the oscilloscope with zero output .

 

what is the wrong ? 

 

/**************************************************** update*********************/

now  when a aligned the data with pdclk negedge so that  ad9957 could load the data correctly.

 

but i found that the pll lock could not go high. and i only changed the cfr1 from 16'h0100_000.

and when the cfr1 register was 16'h0100_0000 , the pll will locked and output correctly.

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