Hello!,

Thanks Rob! This editor is what I needed.

I hope, this drawing is better readable:

       +1.5
2.5V -1.5 |\
   ---------|+ \          RA0
            |    >----+----
          +-|- /      |
          | |/        |
          |     R     |
          +---\/\/\---+
          |
         --- C
         ---
          |
          | R1=R    1:2 RA1
          +---\/\/\---+---
          | R2=R/3 1:4 RA2
          +---\/\/\---+---
          | R3=R/7 1:8 RA3
          +---\/\/\---+---
          | R4=R/15 1:16 RA5
          +---\/\/\---+---

Right, I didn't take into account the noise from current going through PIC

Besides there is a protection diod on any pin with anode tied to ground! The diodes will switch on all resistors when output swings below virtual ground (2.5V) 8-( Because the capacitor starts discharging in that condition ) Will this diod disable any possibility of the plot???

I'm thinking about LDR or digital potentiometers now... Nice thing about LDR is that it can be controlled with only one digital line if you use PWM - needs only RC network for filtering.

Thanks to all who replied.

Nikolai