Trying to alternate blinking of two LEDs

[ak96 4]

Sometimes when I run this code, the LEDs will blink alternatingly, while other times they will blink synchronously. Why is that?  

  

#include <msp430.h>

 

int main(void) {

WDTCTL = WDTPW | WDTHOLD; // Stop watchdog timer

P1DIR |= 0x01; // Set P1.0 to output direction

P1DIR |= 0x40;

 

for(;; ) {

volatile unsigned int i; // volatile to prevent optimization

 

P1OUT ^= 0x01; // Toggle P1.0 using exclusive-OR

 

for(i=0;i<10000;i++){} // SW Delay

P1OUT ^= 0x40;

}

 

return 0;

}

[cubeberg 540]

My guess would be because you're not setting the initial state - you should set them explicitly instead of assuming state when your code executes.  Try P1OUT = 0x00; when you set P1DIR. or instead of P1OUT ^= 0x01, use P1OUT = 0x01;

[ak96 4]

@@cubeberg

 

Yep, that's right. After I set all pins to 0 it started working. The bits are assigned random states every time I run it, and whenever the two LEDs start with the same state it works fine, but when they start with different states they blink synchronously. 

 

Thanks!

[cubeberg 540]

Glad to help!