what is wrong am i doing in this code?

[chitalula]

thanx in advance Henrik. now i want to continue to output constant duty ratio when the comparator input are equal, is it possible to output that constant duty cycle which make input equal to Vref?

[HenrikOlsson]

Hi,
Not sure I understand exactly what you mean. A comparator will only tell you if its positive input is EITHER above or below its negative input. There is no way to tell if the two inputs are "equal". What you COULD possibly do is to use both comparators and create a window comparator which will tell you if the input is below, within or above the window/thresholds.

Or use the ADC...

/Henrik.

[chitalula]

Hi,
Not sure I understand exactly what you mean. A comparator will only tell you if its positive input is EITHER above or below its negative input. There is no way to tell if the two inputs are "equal". What you COULD possibly do is to use both comparators and create a window comparator which will tell you if the input is below, within or above the window/thresholds.

Or use the ADC...
/Henrik.

up to now i dont need to continue to work with the comparator module because it fail to do as i want
i want to use adc but have already read the adcin command but how to use adc to compare the two inputs in the pic i stop there,
can you give me any sample code on that issue?

[HenrikOlsson]

Feedback  VAR WORD
Reference VAR WORD

DeadBand  CON 2         ' +/-, set to 0 if no deadband is needed.

Main:
    ADCIN 0, Feedback       ' Get feedback voltage from Channel 0
    ADCIN 1, Reference      ' Get reference voltage from Channel 1

    ' Now compare the feedback voltage to the reference voltage and include the deadband.

    IF Feedback > (Reference + Deadband) THEN   ' Feedback is higher than reference
        ' Do whatever is needed here.
    ENDIF

    If Feedback < (Reference - Deadband) THEN    ' Feedback is lower than reference
      ' Do whatever is needed here.
    ENDIF
Goto Main

[chitalula]

thaks in advance, am taking a time to concentrate with it and when i meet any difficult i will came back to you