I have developed a board using the AD9958 and it's not working properly. The DDS is controlled by a ATmega on a Arduino board.
I have attached the schematics.
The communication via SPI works, but there is no output on both channels. First I want to run the DDS in single tone mode.
For initialising I send over SPI following.
CSR set to 0xC2
FR1 set to 0xD050A0 (>255MHz, PLLx20, CP 75µA, Single Tone Mode.)
CFTW0 set to 0x0083126E (1 MHz)
After that I read all registers. CSR and FR1 are correct but CFTW0 is 0x00000000. If I select only one channel CFTW0 is read correctly. But there is no frequency on the outputs on both constellations.
I tested Sync_CLK (FR1 0xd05080) and there is an output with 125MHz.
I'll appreciate any hint for the troubleshooting of the problem.