software to control led 0-10v
This is only a part of the total schematic. Do you have them all?
Is this for fluoresent ballasts only? That will maybe explain ISO4.
In professional lighting the 0-10V control is not much in use anymore.
You compare a saw-tooth oscillator signal (which starts at each zero-crossing and runs to 10V as max in 10ms (50Hz mains)) with a comparator. At the output of the comparator you get a PWM signal with a duty-cycle in sync with your mains.
Now you can put the PWM signal (via a optocoupler) to a triac which regulates the power to the bulb.
There is something of this circuit to recognize in your circuit, 555 can be used as PWM generator, but the strange thing is the output(?) to ADC7 and PE2. Were is the controller part?