Yea, I'm reading it with the DMM when it is fully on (255). I also have tried code without the PWM by just using digital write.
@Tesla, two questions:
- Is there any mechanical load on the motor, or is it just spinning free?
- Is the 7805 getting hot?
Something to try, test the drive capability of the MCU. Remove the motor and MOSFET, try to drive a purely resistive load from the ATmega. Connect a 220-ohm resistor from an output pin to ground. Drive the pin high, measure the pin voltage. Now connect the resistor from the pin to +5V and drive it low, again measure the pin voltage.
The motor is just spinning free, and the 7805 is not getting hot. In fact I can't find any part of the circuit getting hot. I tried connecting the 220-ohm resistor and read 4.74V when driven high from output to ground. It measures 0.47V when driven low from output to +5V.
Here are some photos of my circuit.
