My PIC can't do the math! Can yours?

[Ingvar]

If this is all your program is supposed to do, i'd use something like this instead. Much faster.

ADCON1.7 = 1                          'right justified
Loop:
    ADCIN 1,TempRead
    IF tempread>800 THEN tempread=800 'Min. temp.
    IF tempread<650 THEN tempread=650 'Max. temp.
    XF = 301 - ((TempRead - 650)<<1)  '301-((TempRead-650)*2)
    Lcdout $fe,1,”Temp:”, #XF
GoTo loop

/Ingvar

[sayzer]

Thanks for all replies.

When I use "right justified" ADCON1 register, as Jumper and Ingvar suggested, the scale does not behave linear. Thus, I can not match the temp reading with Celsius.

Currently, “left justified” ADCON1 register provides a scale that is perfectly linear and the formula works great (thanks to Paul's catch).

By the way, Ingvar's code is indeed nice but I can not use it.



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