Testing the watch crystal

[legailutin 11]

Hi everyone,

I got really excited when I discovered energia. I had stepped away from ccs for a while after multiple frustrations with a little project of mine. So thousand thanks for this IDE. Already making my programming life a lot more easier.

 

Then to the point. I soldered the watch crystal to the launchpad and wanted to test it with my scope. For that, I loaded the blink code. Just as a reminder, it is supposed to turn the LED ON and OFF every second. However my scope is reading 1.02 seconds.

I went into wiring.c and commented out the

BCSCTL3 |= LFXT1S_2;

line as directed in one of the posting, still to no avail. Am I missing something or my crystal is just not working?

 

Thanks to the community.

[energia 485]

If you have used the Blink example unmodified then it uses delay() which is coming of the watchdog timer that is fed by the MCLK.

I think this example done by xv4y should help you http://xv4y.radioclub.asia/page/5/

xv4y implemented a small RTC library that uses the external crystal to keep time.

[clay_shooter 2]

I used the code on this page http://mspsci.blogspot.com/2010_06_01_archive.html It sets up the timer that can be driven from the crystal. It requires CCS but you should get the general idea.

[paradug 4]

Check out this Instructable for how to tune the clock crystal. This step of the Instructible also includes a simple program so you watch the timing of your crystal on the scope.

 

http://www.instructables.com/id/MSP430- ... -Capacita/

[legailutin 11]

Hi guys!

I'm very pleased with the responses. I actually went ahead and tried the code from viewtopic.php?f=38&t=2688 with the slight modification in wiring.c and it works perfectly: 1sec exactly according to my scope. Now, on to the next step.