Hi!

>        i don't have the working code for the PIC but i can tell you the
>basic idea of PWM. what you do is you start the counter and at the same
>instant set some port bit to one (i.e. high). then you keep on comparing
>the timer value with the digital value, which is supposed to modulate
>the pulse width. e.g. it could be the digitised feed back voltage in a
>PWM controlled poer supply.  the moment the value of the timer becomes
>equal to the digital value, port bit is reset to zero. now the port bit
>will remain low untill the timer overflows. after which new cycle starts.
>        so note that the pulse width is effectively proportional to the
>value of the digital word. larger the digital value more time the timer
>will take to reach the value and hence the pulse width will be larger.
>with the serial ports of 16cxx PICs, it should be easy to get the PWM.
>        i hope you got some idea about the pulse width modulation.

Wow! To tell you the thruth, I didn't quite understand what your tried
to explain to me about PWM! Maybe someone would have a different explanation?
Or maybe just a different way to explain it to me? (Sorry for all does
'explain'!)

Thank you!
Jean-Francois

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Jean-Francois & Alain Joly
jolyal@capitalnet.com