PWM and Rabbit

Would anyone be able to give me a headstart on implementing pulse width modulation with a Rabbitcore 3600?

If someone could explain or provide me with a link, I would appreciate it. I understand the idea of PWM but working with microcontrollers is new to me. I searched the 3600's user manual and it more or less listed that it had the capabilities to do PWM, but did not describe how to use it. I may even be looking in the wrong place for this information but a quick google search was unsuccessful. Thanks!

Brian

Reply to
Traffibm
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I can't help with the specifics, but I can provide you with more information to help you dig.

PWM is also known as "output compare" mode. Look for information about using the timers. It's usually buried in the datasheet somewhere around there.

The way you do PWM on a micro in general:

1) Setup the timer 2) Set the timer in "output compare" mode 3) Set the value at which the output changes stage (0 to 1 or 1 to 0) When the timer overflows, the output will be set to one value. When it hits the "compare" value it will change stages.

So if you have the "compare" value close to zero (if counting up) then you get very little signal, if it's close to the end of the timer period, you get a bigger signal, etc.

ttyl,

--buddy

Reply to
Buddy Smith

Brian,

There is a quite active yahoo e-mail list centering around the rabbits. I'm sure you get help there. Then they also host a lot of application notes on their website and I would be very surprised if no PWM sample would be among them.

Markus

Reply to
Markus Zingg

Thanks for the tips and suggestions. I will check out yahoo and dig into all the datasheets, which I have to obtain from a project teammate.

Just to give some background information on our project, we are in the process of designing a semi-autonomous blimp using a microcontroller(Rabbitcore 3600 Module), an Inertial Navigation System with gyros and accelerometers, sonar sensors, and powerful brushless DC motors. The largest challenge to overcome is weight since helium is lighter than air, but with a 6 foot blimp we can lift about 12 ounces with helium alone. Batteries, even Li-Pos are somewhat heavy in this reference.

Thanks again for the PWM info as it should help us interface these motors to the Rabbit.

Brian

Reply to
MUBill

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