AnsweredAssumed Answered

AD9833 register calculations (frequency)

Question asked by AlanGC on Apr 25, 2016
Latest reply on Apr 28, 2016 by mcee

Hi All

I'm trying to interface AD9833 to 18F452 , the hardware works fine. If I use your calculator link and send the hex code

you suggest then all works fine and accurate. I'm using a 25 Mhz clock to the device.


AD9833 Device Configuration Assistant | Design Center | Analog Devices


My problem is that I'm making an error in the calculation or there is a bug in my complier. I followed your application note AN1070 and my calculation was the same, but higher frequency give a massive error. 


Could you show me how your calculator arrives at  2100 5C29 4A3D 9C29 8A3D C000 E000 2000 for a 4MHZ output @ 25Mhz. Im only interested 5C29 4A3D 9C29 8A3D for Frequency register 0 say.


AN1070 gives a simple example , could you repeat this for 4MHZ ?


Thanks in Advance.