CCS/MSP430G2553: why my little code doesn't work(timer modules)

ozgur terzi

Part Number: MSP430G2553

Tool/software: Code Composer Studio

Hi ,Iwant to when  TA0CCR0=40000  LED  in BIT2  ON  and when TAR=65535  LED OFF.

But the led stays off when I run the program.where is the problem





#include <msp430.h>

 int main(void) {

 WDTCTL = WDTPW | WDTHOLD;         // Stop watchdog timer



    P1DIR |= BIT2;                                     //set output mode pin
    P1SEL |= BIT2;

    TA0CTL |= MC_2 + TASSEL_2 ;         // contunue mode-smclk

   

    TA0CCTL0|=OUTMOD_3;                 // outmod  Set/Reset
    
    TA0CCR0 =40000;

   

while(1)

{  }
    
}

over 6 years ago

0 Eddie LaCost over 6 years ago

TI__Mastermind 47145 points

Hello Ozgur,

Please have a look at the example code below. msp430g2xx3_ta_01.c provides an example which toggles P1.0 when the CCR0 reaches 50000 cock cycles.

https://www.ti.com/lit/zip/slac485

0 ozgur terzi over 6 years ago in reply to Eddie LaCost

Intellectual 260 points

Eddie LaCost said:

Merhaba Özgür,

Lütfen aşağıdaki örnek koda bir göz atın. msp430g2xx3_ta_01.c, CCR0 50000 horoz döngüsüne ulaştığında P1.0'ı değiştiren bir örnek sunar.

https://www.ti.com/lit/zip/slac485

thank you eddie.But The example use interrupt.But I dont want use interrupt.I want learn outmod.So, I want to do this with "outmod".I was trying to practice.I must understand my mistake so that I can master the issue better.I still haven't understood where the problem is in the code

0 Bruce McKenney over 6 years ago

Guru 102665 points

The "real" PWM modes don't work with CCR0, since the "on" and "off" triggers are the same (EQU0).

The only interesting output mode for CCR0 is toggle (OUTMOD_4). If you use that, you'll get a 50% duty output with a period of (2*65k) ticks. If you switch to Up mode, the period will be (2*40k) ticks.

You can get "real" pwm from e.g. TA0CCR1, but you'll have to switch output pins.

0 ozgur terzi over 6 years ago in reply to Bruce McKenney

Intellectual 260 points

I change code TA0CCTL0 |=OUT_MOD_4 Nothing has changed.LEDD always off.

0 Bruce McKenney over 6 years ago in reply to ozgur terzi

Guru 102665 points

> P1DIR |= BIT2; //set output mode pin

> P1SEL |= BIT2;

Per data sheet (SLAS735J) Table 16, P1.2 is TA0.1, not TA0.0. (So actually you wouldn't have to switch pins to use CCR1.) Try:

> P1DIR |= BIT1; // P1.1 as TA0.0 per SLAS735J Table 16

> P1SEL |= BIT1;

and connect the LED to P1.1. If you're using the Launchpad, be sure to remove the RXD jumper from J101.

0 ozgur terzi over 6 years ago in reply to Bruce McKenney

Intellectual 260 points

thank you bruce .

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CCS/MSP430G2553: why my little code doesn't work(timer modules)