The scheme of connection looks thus:
Conclusion Vo LCD is connected by the resistor 470 Ohm to Vss.
The same conclusion (Vo) is connected by the resistor 1 kOhm to one of conclusions PIC16F877A.
The sense of such connection - through the resistor 470 Ohm on LCD acts "-" and contrast maximal.
Through the resistor 1 kOhm on LCD should act "+" and consequently contrast LCD should fall.
How it is possible to realize for PBP program change of a level "+" on conclusion PIC?
