Posted on February 22, 2013 at 00:08I happen to be working on the same thing (with an almost identical motor). To get started with, you'll want to learn how to use the Output Compare Registers on the timers. Basically, these will allow you to generate a PWM signal without using the processor, so the timings will be very accurate.
Take a look at the sample code for PWM out sample code. Its not exactly what you need, but it will give you an idea of how to generate the signal you need to control the esc.
For the average (cheap) brushless esc, you want to generate a pulse that is 2ms long for full throttle. A 1ms pulse corresponds to 0% throttle. Values in between will yield different throttle percentages. Basically, if you set your base frequency at 1/2ms Hz and vary the duty cycle between 0% and 100%, you will have the wave you need. The problem I am running into is that you can't send these pulses to the ESC too fast. Each pulse must have some down time between it and the next pulse. This time does not have to be very long, but my research says it should be at most 400Hz. If you're using cheap ones like me, then that number needs to be more like 150-200Hz. So basically, you are sending pulses that are 1-2ms long however fast your esc will take them. Figuring out that speed is just trial and error.
I hope someone else can give some insight on how to set up the timers for this. I have mine running to where the auto reload value gives a nice 1-2ms pulse, but the timer is running at 1MHz, which is way too fast for the ESC. What we need is the timer to run somewhere around 200Hz and have the auto reload value (ARR) produce the pulses. I'm having trouble figuring out what prescalers to use on that. If I get something working, I'll post my code. I hope this helps.
