Arduino Due PWM Frequency Moderators: adafruit_support_bill, adafruit

[rubidium]

Any simple way(s) to raise the PWM frequency (on pins 2-9) from the default 1 KHz? I'm driving some fans and getting a nasty 1KHz "whine" that I'd like to eliminate.

[adafruit_support_mike]

It seems to be possible.. this thread from the Arduino forums discusses the subject: http://forum.arduino.cc/index.php?topic=131323.0

[rubidium]

Looks like making the following simple changes in variant.h in the Arduino library did the trick, and doesn't appear to mess up things like delay(), micros(), or ADC sample rate. I'm now getting 20KHz PWM on Pins 2-9.

Code: Select all | TOGGLE FULL SIZE

...
/*
 * PWM
 */
#define PWM_INTERFACE      PWM
#define PWM_INTERFACE_ID   ID_PWM
//#define PWM_FREQUENCY     1000    // <----- original
#define PWM_FREQUENCY      20000    // <----- change
#define PWM_MAX_DUTY_CYCLE   255
#define PWM_MIN_DUTY_CYCLE   0
#define PWM_RESOLUTION      8

/*
 * TC
 */
#define TC_INTERFACE        TC0
#define TC_INTERFACE_ID     ID_TC0
//#define TC_FREQUENCY       1000    // <----- original
#define TC_FREQUENCY        20000    // <----- change
#define TC_MAX_DUTY_CYCLE   255
#define TC_MIN_DUTY_CYCLE   0
#define TC_RESOLUTION      8
...


[moshang]

Thanks @rubidium - this was exactly the solution to my problem today.