10 years, 5 months ago.

Strange behaviour of PWM on Nucleo

I made sure the firmware was updated on my Nucleo F030R8 board. I attached a common anode tri-colour LED between 5V with a 200 ohm resistor and D9, D10, D11. I can use RGB blinky code successfully with these o/p pins, but if I use PWM, then only red and green works - blue comes out as green. If I comment out the red code, then blue and green works OK. Can the mbed software only handle 2 PWM signals, and if using more it gets scrambled? Perhaps some pins are dedicated to a particular PWM signal - where can I find this info? Tony

Here is the code:

1. include "mbed.h" change to o/p pwm to tricolour LED - afa - 3 June 2014

PwmOut redpwm(D9); PwmOut greenpwm(D10); PwmOut bluepwm(D11);

int main() { int i; redpwm.period_ms(10); greenpwm.period_ms(10); bluepwm.period_ms(10);

printf("pwm set to %.2f %%\n", mypwm.read() * 100);

while(1) { for (i=0; i<11; i++) { redpwm.pulsewidth_ms(i); wait(0.2); } for (i=0; i<11; i++) { greenpwm.pulsewidth_ms(i); wait(0.2); } for (i=0; i<11; i++) { bluepwm.pulsewidth_ms(i); wait(0.2); } } }