MSP430FR6972: SMCLK frequency problem

Hardy Ma

Part Number: MSP430FR6972

I have a question about FR6972, I timed 225us on a 12-timer for 900 cycles and found that the time was 80% of normal.Timer clock is SMCLK,SMCLK clock source is DCO(4M).What causes the timing time to become shorter?

over 5 years ago

0 Eason Zhou over 5 years ago

TI__Mastermind 32870 points

Hi,
1. How can you reach a conclusion that he time was 80% of normal?
2. Can you give some phenomena? Use a oscilloscope to catch the wave?
Eason

0 Hardy Ma over 5 years ago in reply to Eason Zhou

Intellectual 470 points

HI Eason:
It's a probabilistic phenomenon,the waveform was not preserved,is there any suggestion to troubleshoot the problem?Thank you .

0 Eason Zhou over 5 years ago in reply to Hardy Ma

TI__Mastermind 32870 points

Hi Hardy,
It seems to be a difficult thread. Can you give more information?
1. What the application of MSP430?
2. What will happen, when time is 80% of normal? How can you find it?
3. At which condition, it will cause this phenomena?

If you want to catch the jitter of a PWM, you need to a steady comparison source.
1. Use a oscilloscope and set the trigger to keep the wave on the screen to be steady. Then if it is not steady, problem happens.
2. Use a compactor peripheral of a MCU to catch the wave.
3. Use a LED and see by your eyes.
Eason

0 Eason Zhou over 4 years ago in reply to Hardy Ma

TI__Mastermind 32870 points

Hi,
Is there any progress?
Eason

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MSP430FR6972: SMCLK frequency problem