how to compare to analog signal.... pic184f331 - Electronic Circuits Projects Diagrams Free

chinusneha · 23rd January 2009, 03:46 PM

hi friends ,

i want to compare to analog dc signal & want 2 change the duty cycle of PWM according to the error signal... how can i do that??

if someone having C code... plz help me....

duffy · 25th January 2009, 05:44 PM

You setup the A/D, run the conversion, get the numbers out of ADRESH & L, scale them with a multiply instruction, offset them them with an add or subtract, then load them into the PWM registers.

Usually. If a linear relationship won't do it, you may have to write a big lookup table. If the whole thing needs to be a PID loop, that's even more fun. Start with the basic linear function, though.

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23rd January 2009, 03:46 PM	#1
chinusneha	how to compare to analog signal.... pic184f331 hi friends , i want to compare to analog dc signal & want 2 change the duty cycle of PWM according to the error signal... how can i do that?? if someone having C code... plz help me....

25th January 2009, 05:44 PM	#2
duffy	You setup the A/D, run the conversion, get the numbers out of ADRESH & L, scale them with a multiply instruction, offset them them with an add or subtract, then load them into the PWM registers. Usually. If a linear relationship won't do it, you may have to write a big lookup table. If the whole thing needs to be a PID loop, that's even more fun. Start with the basic linear function, though.