Hi again Hans, thanks for your answer.

I mean it every time act as current value was not equal previous, process and send midi, so if controller 1 is in 23 it sends: 23,23,23,23,23,23,23,23,23....

I have certain it is not READ subroutine because it was really working, could even make a presentation with it without problems, the only faulty was sending values twice.

I was working on it all day today, and I think I could solve it with really minor change to old code, it is working very well so far. Please can you take a look? I want to thank you and all other people for all help and attention you gave me, so, THANKS.

I have changed READ by READADC, on SEND subroutine value on A is shifted(losing LSB)

READ0:  CALL READADC        ; Read ADC
        MOV TH,A
        MOV TP,@R0          ; Remember previous value
        CLR C
        SUBB A,TP           ; Current - Previous
        JNC ABSEND          ; If carry: result was negative, CPL IT!
        CPL A
        INC A


ABSEND: CJNE A,#2,TRESADC   ; Compare change to deadzone
TRESADC:JC INCI             ; less than value. ignore
        MOV A,TH
SEND0:  MOV @R0,A           ; Update ram value with new one
        CALL SEND
        
        
INCI: .............