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AD9914 Eval Board: DAC Cal and PLL Cal

Question asked by tnagy14 on Jun 2, 2013
Latest reply on Jun 2, 2013 by LouijieC

I am using the AD9914 Eval board with SPI communication to an Arduino.  Can someone confirm the correct or best way to issue the DAC CAL and PLL CAL.  I have tried both of the following and do not see any difference in the output quality, is either correct? I also have tried no calibration at all and still the get same output (which looks stable).  How can I confirm the calibration was done successfully?

 

The difference between the two options is simply when to pulse IO_UPDATE.  Is it required to do it between the two writes to CR 4?

 

1st:

....

write     0x01010002   //CR 1, PLL Cal bit 24 HIGH

Write    0x00800000   //CR 2

Write    0x00040C1C  //CR 3

Write    0x01052120   //CR 4, DAC CAL bit HIGH

Write    0x00052120   //CR 4, DAC CAL bit LOW

Write    Frequency Tuning Word

Pulse IO_UPDATE

 

2nd:

....

write     0x01010002   //CR 1, PLL Cal bit 24 HIGH

Write    0x00800000   //CR 2

Write    0x00040C1C  //CR 3

Write    0x01052120   //CR 4, DAC CAL bit HIGH

pulse IO_UPDATE

Write    0x00052120   //CR 4, DAC CAL bit LOW

Write    Frequency Tuning Word

Pulse IO_UPDATE

 

 

Thanks

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