Yes, that's the problem. The RBC_INT react with pin RB.0 on port B, because this pin operate the LCD ENABLE pin. If I try to use only portA to operate the LCD (with internal 4MHz oscillator) and on the PORTB pin RB.6 and RB.7 hang only the encoder A and B channel, rest pins configured to output the reading is perfect. Always after turning up and down randomly, slower, quicker etc. when I return to marked starting position the reading is zero. Now, how to solve this problem, how to "tell" to MCU the only pinRB.6 and RB.7 trigger the interrupt, not the entire portB