Hey everyone. After a frustrating day, I have finally been able to get the ATtiny 817 Xplained to program, however, I am having problems getting the DAC to work. In the mean time, while I try to get the DAC figured out, I implemented a PID algorithim in Arduino. I am taking measurements from a GY-521 IMU/Temperature Sensor, and outputting to PWM. At the moment, I do not really have a system to control, so I have just been changing the temperature with my finger, to warm the sensor up, and blasting it with an upside-down can of electronics duster to cool it down. 

I should have an actual system to control soon, and will hopefully be able to use the Xplained board.

In this image, the blue line is the measured variable (PV), and the red is the PWM value (CV). As always, if anyone has any questions, suggestions or critique, please feel free to comment.