Timer works only with CCS debugger

[JohnDough 1]

Hi,

 

I have a very simple program,

which writes a message to oled,

and then start "Timer A" to blink the internal led.

 

The program looks to work fine when I execute it from CCS using "Debug".

(Code Composer Studio, Version: 6.1.1.00022)

 

But when I just connect it to USB for power,

or hit the "reset" button,

the program executes the code before the timer,

but the timer interrupt is not working.

 

The code for timer was taken from here (2nd example: "Using the Timer")

http://www.crash-bang.com/getting-started-msp430-timers-3/

 

I suspect it is something with the settings of timer, not with CCS,

but I dont know what can cause this problem.

 

Thanks for any help.

[tripwire 139]

Which MSP430 are you running this on, and what board/launchpad are you using?

 

Also, what does your main() function look like? I'm particularly interested in the Basic Clock System setup code.

[JohnDough 1]

@@tripwire

 

I'm using MSP-EXP430G2, G2553

 

From main, this is the code which looks relevant to me:

 

 

// init for oled

    WDTCTL = WDTPW | WDTHOLD;                // Stop watchdog timer
    DCOCTL = CALDCO_16MHZ;                  // Set DCO for 16MHz using
    BCSCTL1 = CALBC1_16MHZ;                 // calibration registers

 

// init for timer

    TACCTL0 |= CCIE; //Enable Interrupts on Timer
    TACCR0 = delayCycles; //Number of cycles in the timer
    TACTL |= TASSEL_1; //Use ACLK as source for timer
    TACTL |= MC_1; //Use UP mode timer

 

// loop

    while (1)
    {
        _bis_SR_register(LPM3_bits + GIE); //Enter Low Power Mode 3 with interrupts
    }

[terjeio 134]

@@JohnDough What is your ACLK source and the delayCycles value? Is the LED partly lit?

[tripwire 139]

@@JohnDough What is your ACLK source and the delayCycles value? Is the LED partly lit?

 

Also, do you have the watch crystal soldered onto the launchpad or not?

[JohnDough 1]

@@terjeio

 

Your question "What is your ACLK source" led me to do a small research -

I added this line:

 

BCSCTL3 |= LFXT1S_2;

 

and problem solved.

 

Oddly, it was missing from the example I used which was specific to timers.

 

Thanks for your help !

[JohnDough 1]

@@tripwire

 

Also, do you have the watch crystal soldered onto the launchpad or not?

 

Sorry, I missed your message before.

Not yet, this is my next task.

 

Thanks for your help !

[JohnDough 1]

 

A question regarding soldering the crystal:

 

It looks my soldering skills need to be improved...

I failed to solder the crystal, and now I need to buy a new one. 

 

The crystal which came in the kit is this one:

http://www.microcrystal.com/images/_PDF/2_Crystal_Metal-Package/MS3V-T1R_Pd.pdf

 

And according to "how to solder" - "MSP 430 launchpad soldering Crystal" 

tutorial in YouTube

 

There are 3 points to solder: the 2 legs and the body.

 

My local supplies store has this one in stock:

https://www.sparkfun.com/products/540

 

But this one seem to have only 2 legs, and the body is in "barrel" shape,

which doesnt look like intended to be soldered to the board.

 

So my question is:

Can the crystal from the sparkfun website can be used instead ?

Do I need to solder the "barrel"/body ?

 

Thanks for your help.

 

 

[tripwire 139]

So my question is:

Can the crystal from the sparkfun website can be used instead ?

Do I need to solder the "barrel"/body ?

 

It looks like the sparkfun crystal is slightly bigger than the stock launchpad one. It's also a through-hole part rather than SMT. I think it would be possible to push the leads through the plated through-holes on either side of the pads used by the stock SMT crystal. Then you could solder the two wires from the back of the board, which might be easier than surface mounting.

 

The body connection can probably be made with the sparkfun crystal even though it doesn't have a flat underside. Having said that, the body connection is not essential. It grounds the case, which helps to shield against any interference. It should still work just fine without it, and it's better to leave it unconnected than to overheat the crystal if you're finding it awkward to solder.

[JohnDough 1]

@@tripwire

 

Thanks a lot for your help !