Pulse Width Modulation

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Jessica Shaw

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Oct 1, 2014, 2:41:18 PM10/1/14

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Hi,

I am new to MSP430 series microcontroller. I am trying to do pulse width modulation. My code is as follows

#include <msp430.h>

int main(void)

{

WDTCTL = WDTPW + WDTHOLD;

TA1CCTL0 = 0x0040;

TA1CTL = 0x0110;

TA1CCR0 = 655;

TA1CCR1 = 327;

P2DIR |= 0x02;

P2SEL |= 0x02;

//TA1CTL = TASSEL_1 + MC_1 + TACLR;

__bis_SR_register(LPM3_bits);

// __no_operation();

}

MSP430F5438 counts up to 655 with no problem. I get 50Hz time period. The clock is 32KHz. The problem is that MSP is not taking the "TA1CCR1" value "327" into account. "327" suppose to give me 50% duty cycle. I am not able to control the Duty Cycle. The time period is correct 20msec but I have no control over Duty Cycle. Please advise!

jess

Hans Henry von Tresckow

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Oct 2, 2014, 2:57:29 PM10/2/14

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I think the problem is that you never set up TA1CCTL1 to define the output mode for the pin.

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