Mini Maestro 12: Sinusoidal PWM?

Support Servo controllers and servos
#1

It should be possible to vary the on-time to achieve a sine wave PWM signal on channel 8.

In theory what are the max and min limits of the frequency of such a sine wave?

Please explain the dependency on the clocking rate and what that would be.

Thanks

#2

Hello,

You can approximate a sine wave with a high frequency PWM that is filtered/averaged by further circuitry.

There is no limit on the minimum PWM frequency - you can always make your program slower. You can only update the PWM value a few thousand times per second, so the maximum is probably less than 1000 Hz.

I think you should use a very short PWM period. You can have almost 10-bit resolution with a 47 kHz PWM (period = 1020) or 8-bit resolution with ~200 kHz PWM (period = 255).

-Paul

#3

Thanks for a speedy reply.

Does Pololu publish the number of clocks data for the command reference set?

#4

Hello,

I have no idea what you mean by “number of clocks data” or “command reference set”, but the entire Maestro documentation is here. In particular, please look at the “Set PWM” serial command and tell me if you need more information than what it says there.

-Paul

#5

Hi

The command reference is section 6b of the user manual.

I am asking for how long the Maestro takes to execute each command and keyword in that reference. I call it clocks data - you may call it different.

#6

Hello,

We do not have that data. It will be different for every command and sometimes even depends on the arguments to the command. Also, there are other tasks being performed by the Maestro in between executing script commands, so the speed of your program will depend on what else you are doing.

-Paul