I just got an AD9914 eval board with the intention of generating short (1 us) phase stable chirped pulses. I have been able to generate the pulses using the board by setting the no dwell high pin, and typing in the relevant frequencies and sweep rates into the sweep tab of the evaluation board software. However, in order to tell the board to start a pulse I have to hit the 'up' and 'down' buttons repeatedly in the software. This is OK, but I would like to sync up the pulse triggering with some other electronics.
I looked through the datasheet and it seems that the the 'up' and 'down' buttons are linked to the DRCTL logic pin. With this info I traced the DRCTL input on the AD9914 chip (input pin #63) to the P102-DRCTL-BUF external header connector. When I monitor this pin it goes to ~2.2 V when I push 'up' and 0 V when I push 'down' - in other words it seems to be the right place to trigger the board. Next, I tried applying a 10 Hz square wave (0-2.2 V) to this connector to mimic the signal that goes through when I push 'up' and 'down', but it does not seem to trigger the board.
I was wondering if anyone knows how to externally trigger the DRCTL pin using a square wave? Any other suggestions for triggering the AD9914 would also be greatly appreciated.