MSP430F5438A: Migrating from non-A part and oscillator is not running at same frequency...it is slightly off which messes up our application.

Kenneth VanDeWater22

Part Number: MSP430F5438A
Other Parts Discussed in Thread: MSP430F5438

We have a device running the MSP430f5438 off of a 16MHz (18pf) crystal. Our application reads frequency signals and the A part seems to be off enough to mess up our calculation. We built several units with the non-A part and verified they functioned appropriately. We then replaced it with the A part with recompiled code and the frequency calculation is now off by too much and seems to vary between units where the non-A part did not vary at all. I have tried adjusting the drive strength with no change noted as well as the VCORE and still no change. Not sure what else it could be.

over 5 years ago

0 Johnson He over 5 years ago

TI__Mastermind 30406 points

Hi,

Attach the different between 5438 and 5438A as your reference:

https://www.ti.com/lit/an/slaa419c/slaa419c.pdf

Thanks!

Best Regards

Johnson

0 Kenneth VanDeWater22 over 5 years ago in reply to Johnson He

Prodigy 30 points

Yes, I used that application note for reference, but it does not shed any light on my problem.

0 Bruce McKenney over 5 years ago

Guru 102905 points

Can you quantify? The first thing I'd do is put SMCLK out on a pin (e.g. P1.6) and measure it with a scope. It could be some other difference masquerading as a clock-speed thing.

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MSP430F5438A: Migrating from non-A part and oscillator is not running at same frequency...it is slightly off which messes up our application.