In the setup code you will just need to define what pins you have used for what job between the DDS board and the Arduino.
#define data_pin 12
#define load_pin A5
#define clock_pin A4
#define clock_hz 120000000LL
dds ddschip(DDS9850, data_pin, load_pin, clock_pin, clock_hz);
This sets my dds up with its 120mhz onboard crystal. I am substituting the pin numbers with words to make it easier to understand. For example the word data_pin would be replaced everywhere it is found at compile time with the number 12. this is what the #define
Now the chip pins have been defined, we can just use the ddschip.setfrequency(Frequency); command to set the frequency to any frequency we desire, within the capabilities of the device. The AD9850 boards i have used are pretty good for about 0-40mhz, beyond that they are a little sketchy.
I figured that i would use the up and down buttons to raise or lower the frequency.
I decide to use the left and right buttons to cycle the amount the frequency would increment on raising or lowering. I chose, 1Hz, 10Hz, 100Hz, 1KHz, 10KHz, 100KHz and 1MHz.
I cobbled together some code, some of which i hacked out of a previous LCD keypad project (Morse coder). I have kept the interface reasonably simple, after all we only have 16 characters on two lines.
After I had it built up on the bench and had tested it extensively I decide to put it all in a box. Initially i wanted to put a battery pack inside the box as well, but decided to leave access to the power jack so i could just plug in a battery pack externally if i wanted to. The result are the photos you see here. The LCD keypad shield is designed to be used in the open and not really designed to go in a case, but i shoehorned it in with lots of cutting. I used a terminal block on the side for the sine wave output and I also decided to break out the square wave output and its associated adjustment pot, the LCD contrast adjustment pot and the DDS board power light.