MSP430F5659: Unable to start XT1 (LF Oscillator), XT1LFOFFG = 1

stomp

Part Number: MSP430F5659
Other Parts Discussed in Thread: MSP430F5529,

Hi,

We are bringing up boards with MSP430F5659 devices which are an alternate for us from the MSP430F5529 devices, and apart from the different device, the crystals, capacitors, etc are identical between the boards.

We can't get the XT1 LF 32.768K oscillator to start on MSP430F5659 despite trying everything from different crystal manufacturers to different capacitor values. The crystal setup and clock setup code work perfectly on MSP403F5529.

There is no errata, no port pins that need configuring and nothing else that we can see that could cause the XT1 not to start.

Would anyone know if there are any specific differences between '5529 and '5659 variants with respect to the TX1?

Thanks

Stomp!

over 6 years ago

0 Nathan Siegel over 6 years ago

TI__Genius 10980 points

Hi Stomp,

I think you may be seeing the same issue that is discussed in this thread: e2e.ti.com/.../1999606

In short, you need to clear the LOCKBAK bit inside of the BAKCTL register. Please see the above thread for more details.

Regards,
Nathan

0 Ryan Brown1 over 6 years ago

TI__Guru**** 202216 points

Hi Stomp,

Are you able to share your board schematic and layout images with us? What crystal and capacitor variants have you tried? If you were to program the msp430f665x_lpm3_01.c example code, does it get stuck in the fault flag loop?

Regards,
Ryan

0 stomp over 6 years ago in reply to Nathan Siegel

Genius 4615 points

Hi,

I searched for ~30 min for this answer, I think SNR was low on this topic.

The LOCKBAK bit did the trick, the XT1 oscillator is now working well.

Thanks again!

Stomp!

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MSP430F5659: Unable to start XT1 (LF Oscillator), XT1LFOFFG = 1