Goal: To be able to write a byte to the PWM register, and have that number appear on the LCD. I don't need all 3.5 digits of range, I just want 0 to 255.

The inputs of the CX101B must be isolated from the supply ground (unless it's a CX101BG), and a difference of 200mV will result in full deflection - 1999. Thus, for 0-255, I need to be able to present a voltage difference of 0V-25.5mV.

Question: If I wire the circuit up like so...

 PWM pin-------v^v^v--------v^v^v--------v^v^v------GND
                1.0M    |     X     |     1.0M
                       in1         in2