i.MX51 buzzer driver using IO

[alsaleem]

Hi,

Is there a way to output a variable frequency signal (audio range, 200-4K) square wave from i.MX51 to drive an external buzzer?

Thanks.

[JerryFan]

That's right, PWM is designed for brightness tuning, but it can also be used flexibly.  Actually, the PERIOD can be programmed (see Chapter 47.2.2.5, mx51RM for the detail.)  and  the frequency is much accurate that GPIO way. Anyway, if the accuracy  is not important, such as for a buzzer, the GPIO method should be OK.

[alsaleem]

The driver only allows to set the pulse width not frequency (fixed on initialization) using brightness. How do I change the PWM frequency?

Thanks.

[JerryFan]

PWM was recommended for this case. It is more accurate and need less arm core's involvement.