On Mar 16, 2:24 pm, "petrus bitbyter"
wrote:
"eddie" schreef in ooglegroups.com...

I am trying to program a pic micro 16f877 to desplay the rpm of a
motor on a lcd. I as using a sensor which gives me 4 puls per
revolution of the motor shaft. I am trying to use the capture and
compare property if the pic . can anyone help me . Anyothe method to
do the same procedure is appreciated.
thank yo

Any idea what the pulses you get, will look like? Any idea about minimum and
maximum speed expected? Have the PIC16F877 datasheet already? Read it? (It's
only about 200 pages and you will not need all of them.) I may be wrong but
from your post I got the idea that someone told you to start this project
but that you have hardly an idea how and where to start. You even seem to
have no feeling about what you really want to measure. Who told you to use a
PIC16F877? Nice chip but quite a gun to kill a fly. Advise you'd better
think over the basic idea of rpm and ways to measure it. Then look for how
to use a micro to do so.

petrus bitbyter

As you should know i can only put 5v into the pic and the puls am
getting goes from 0 to 5 volts. its square waveform.Its part of a
ptoject yes...and i choses this 40pin device because i have other
things which i have to impliment on the project.Its a small 12v Dc
motor which am trying to find the Rpm . minimum rpm i want to desplay
on my Lcd is 400 and maximum is 1500. I have got the data sheet and
some other aplication notes from the microchip website and have been
reading it thats why i mentioned about the capture and compare
function of the pic. All the other part of the porject i can
handle ..i need just a little help on makin the pic calculating the
RPM. I dont have much knowlwdge on assembler language so am using C.I
am using Mplab with Hitech compiler.
anyhelp is appreciated