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Basic non-USB operation of AD9914 AD9915 EVAL Board

Question asked by jpotter0 on Jan 2, 2018
Latest reply on May 24, 2018 by Tanzir

I am trying to use the AD9914 EVAL board controlled by a microcontroller instead of the USB. I see how to set the jumpers to set the connections to the USB chip to a high impedance state, but I am confused about the requirements for setting up the registers.

 

I want to do something fairly simple. I need a programmable output frequency, and programmable amplitudes for four profiles, which I propose to select by the inputs to PS0 and PS1.

 

I set the board up and got it working through the USB port. I then copied the data for the four control registers. With the microcontroller and can send SPI data and clock to set the input registers. I am using CSB to select the chip. Even though i have only one chip at moment. After setting the data in the serial input registers I issue an IO_UPDATE pulse to transfer the data. Right now I am putting a dc signal on the PS0 input in hopes of seeing a CW signal. So far nothing.

 

I have done this with the AD9959 successfully.

 

I am uncertain whether or not anything will work without synchronizing the IO_UPDATE with the SYNC_CLK. That does not appear to be necessary for the AD9959, for example. The timing of the update is not critical for my application.

 

Also, I have read the the PSx pulses have to be synchronized with the SYNC_CLK in order for the profile selection to occur. Right now that isn't an issue. I'd be happy to see an output of any kind.

 

I need a simple guide for using the EVAL board to get any output with my microcontroller.

 

Thanks,

 

Jim

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