I am trying to figure out how to program the AD9913 synthesizer IC using an SPI bus. To do so I am using an STM32F407 µC ‘ SPI Interface which I level shifted using an resistor diode combination (see circuit.png) that is connected to the AD9913 Demoboard (JP2-> Manual). Unfortunately my attempts all failed so far – it was not possible to get the AD9913 to work. Using the AD9913 Demoboard’s onboard programmer it works so far. I’ve recorded the programming sequence and reproduced the same sequence using the µC SPI buss (see scope.png). The reset pin was pulled up to 1.8V for approximately 2 ms before 10 ms later the programming sequence started. After the programming sequence was over PSO &PS21 where pulsed up to 1.8V and PS2 was pulled down to ground. In contrast to the on board programmer the result of my own attempt to program the AD9913 is no result at the DAC output. Since AD didn’t included an SDO pin unfortunately I’ve also no idea how to read the state of the AD9913 registers using SPI.
Since I’m out of ideas what else I might change to succeed I would be very glad if someone could give hint.