Playing with a DC motor

So I got the DC motor yesterday and all the chips to run it with.

Here's my setup with the motor:

The motor is a 4.5-15V up to 22W with a 750:1 gear reduction. But it seems I got the wrong motor. You see I mixed up RPM and RPS in my head for some reason. Haven't worked with motors before so.. But still pretty embarrassing. Don't tell anyone.

I'm using a RECOM R-785.0-0.5 DC/DC converter to make 5V for the logic chips out of the supply voltage (works in wide range so good for my testing).

Motor is run using an Allegro 3953 full-bridge PWM DC motor driver. One thing to note here is that I burned my first chip at motor braking testing, probably because I didn't bother to properly setup the sensing pin. Then again I haven't dared to retry braking using my second and currently only chip. There was some smoke, panic and excitement. Fortunately it seems nothing else burned.

And everything is controlled with an ATMEGA48 microcontroller. I moved on to using its PWM functionality (instead of the inbuilt PWM of the Allegro) to modulate the motor.

Now I've been playing with this motor here to get an idea how it works but found another way to play it. Forgive the pun. Here's a video:

Basically, when doing very high frequency PWM the shaft inside the motor tends to just vibrate. Here's a better melody, a known tune by Beatles: