This is a modified version of basic wave generator design with AD9850
In order to get a frequency you’ll need to enter a 3 digit number. For example for 123 Hz enter 1, 2, and 3.For 5Hz enter 0, 0, and 5. Select the range by pressing “*” key – it will cycle trough Hz, KHz and MHz ranges (MHz – not implemented yet).Press “#” to load the number into AD9850.
Generated frequency measured by UT71D
More about the code. PIC is constantly searching the keypad. As soon as 3 digit numbers are entered they are converted to binary by BCD to binary routine and then multiplied by a range constant to produce a valid frequency word for AD9850.