I am working on a project that requires a variable frequency square wave as an input to an A3977. I currently have it working well using just an Arduino uno, using the "blink without delay" idea. The problem that I have is that the Arduino needs to be used for other processes, with serial input and output. Each time the Arduino reads or writes the serial, there is a slight disturbance in the generated square wave. This is not an option, unfortunately. What I would like is for the Arduino to receive the appropriate instruction (the frequency of the wave) and set another IC accordingly. This way the brunt of the work is processed by the IC, not the Arduino. I have been looking at avrious options, including an AD9833, which may be unnecessarily complicated for this application. Another option is to use an ATTiny84, which is where my question comes in. If I were to go with the ATTiny84, and chose to continue with the "blink without delay" thing, would it be possible for the arduino to send this instruction? My thinking is that I could write a basic sketch for the ATTiny84 using the Arduino IDE, and use the serial input to change the length of the the on / off phases of the wave...is this feasible?
Any help would be greatly appreciated,