real number from pic ???

Discussion in 'Embedded Systems and Microcontrollers' started by capacitor1, Jan 12, 2013.

  1. capacitor1

    Thread Starter New Member

    Jan 12, 2013
    10
    0
    Hi!

    I have an angle in the microcontroller from 0 to 360 , and I want to calculate its Sin , and display this number as analog .

    I use CCS compiler , and I think that the Math library exists.

    the hard thing how to convert the number from 0 to 1 ( if we neglige the negatif numbers ) , and with 3 digits after the point . (0.000,0.001,....,0.999,1.000) to a voltage .

    Ex: if the angle=60 : sin(60)=0.8660254≈0.866 ===> 0.866V

    thanks
     
  2. MrCarlos

    Active Member

    Jan 2, 2010
    400
    134
    Hello Capacitor1

    Surely this information can help you:
    especially reads the content of the page 363.
    It says SinE3 function is implemented as a lookup table.
     
  3. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    If you want to output the voltage to read on a multimeter, etc, you can use a PWM pin / software PWM, and a resistor capacitor filter to make it into a stable voltage.
     
  4. nigelwright7557

    Senior Member

    May 10, 2008
    487
    71
    When I did assembler I just used a 90 value look up table.
    I mirrored for 90-180 then made negative from 180-359 degrees.
     
  5. capacitor1

    Thread Starter New Member

    Jan 12, 2013
    10
    0
    Hi

    thanks for your help, but the second part that i have to convert it to a real number in volts ??
     
  6. WBahn

    Moderator

    Mar 31, 2012
    17,748
    4,796
    What do you mean "convert it to a real number in volts"? This doesn't make a lot of sense, just like saying "display this number as analog" doesn't make a lot of sense in your first post.

    Are you saying that you need to output a representation of it as an analog voltage? If so, what conversion factor are you trying to get (how many volts per degree)? What about negative angles?
     
  7. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    If you want AC out, You will need a DAC (Digital to Analog Converter

    An approximation can be made with PWM + low pass filter.

    Depends on the accuracy you desire as to which method you choose.
     
Loading...