PWM frequency, is 25kHz possible?

Hardware
1

Hello

I want to control a 4-pin PWM FAN (computer casing) using the imp. It seems that norm for the PWM control for 4-pin computer fans is 25kHz.

I remember from arduino that this was somewhat complicated to obtain, how is the case for the imp?

2

This is how I did it last time I was playing with a 4pin pwm fan from a computer. They are not that picky about the frequency, but if you set it too low you can hear it.

3

Great, thats perfect, thanks Mike!

4

25kHz PWM is no problem for the imp, see http://electricimp.com/docs/api/hardware/pin/configure/#sts=pin.configure(PWM_OUT, float, float)

You’d just specify the period as 1/25,000ths of a second. Note the 1.0 (vs 1) to ensure that you get a floating point value here:

hardware.pin1.configure(PWM_OUT, 1.0/25000, 0.5);

…this sets 25kHz, 50% duty cycle on pin 1.