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3 pwm signals and only 2 pwm capture pins in PIC?

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asic1984

asic1984

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pwm and pic?

hi all

in my project there are 3 sensors which output in pwm signals the problem is that i have only 2 pwm capture pins in the pic 18f452 ........so how can i come over that keeping using these type of sensors ...........are there any ic that may convert this signals into analog signals so i can receive them again in the adc of the pic

or are there any suggested solution

thanks
 

Re: pwm and pic?

Hi,
You could try and low pass filter [smooth] one of the PWM signals and feed it into the ADC input [via buffer amplifier..gain etc]
or multiplex two of the PWM signals together and feed into the PWM input... a couple of AND gates plus inverter controlled from a output pin would do this
 

Re: pwm and pic?

hi

thanks for your help but can u explain more :

how can passing the signals int low pass filter output used ......i donnot think it will represent an analog value !
 

Re: pwm and pic?

This is normal practice to convert digital-to-analog: PWM output feeds a low-pass-filter cosisting of a resistors and a capacitor + a buffer. As you know a PWM is a square wave with differen pulse widths. This means that the duty cycle of a square wave is different, so is its average current: this average current (after LPF) is your analog value ..
 

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