MSP430F5658: RTC reads zero after call to PMM_setVCore

Mark Hubelbank

Part Number: MSP430F5658

We are using the support code for the USB interface on the MSP430F5658. When starting this code it makes a call to PMM_setVCore(PMM_CORE_LEVEL_2);. just prior to this call the RTC works properly and returns the current time. After the call all time registers (RTCMIN, RTCSEC.....) return zero. Only a chip reset seems to make this recover. When it does recover, the time is correct, the clock had not stopped. Both before and after the call, the LOCKLPM5 bit is zero.

In the PMM_setVCore code there is a note that it is highly modified to address "erratum FLASH37". I was unable to find this document.

Any suggestions that would allow the proper operation of the RTC while in the USB support code would be appreciated.

over 7 years ago

0 Eddie LaCost over 7 years ago

TI__Mastermind 47505 points

Hello Mark,

I apologize for the delayed response during the holidays. Are you still experiencing this issue?

I am also looking for the FLASH37 errata and do not see it listed in the errata sheet. I will keep searching for this.

0 Mark Hubelbank over 7 years ago in reply to Eddie LaCost

Intellectual 470 points

Yes, the problem still exists. The only work around is to read the clock before enabling the USB (really switching the clock to USB mode) and then letting the timer interrupt increment the time while in "USB" mode. So far, the only thing which seems to re-enable the access to the RTC registers is a chip reset.

0 Eddie LaCost over 7 years ago in reply to Mark Hubelbank

TI__Mastermind 47505 points

Mark,

Sorry for the delay. I am back to researching this and hope to have some suggestions shortly.

0 Mark Hubelbank over 7 years ago in reply to Eddie LaCost

Intellectual 470 points

That would be helpful. The only work around so far has the potential to lose some time in the switch out of "USB mode" and thus be inaccurate.

0 Eddie LaCost over 7 years ago in reply to Mark Hubelbank

TI__Mastermind 47505 points

Mark,

When you check the time registers and returns zero, are you checking this in the debugger or externally(via UART, etc)? If using the debugger to check this, it is possible that after setting the vcore level, the debugger is not reporting properly. You may want to try dumping the data via UART to confirm.

You may also want to consider setting vcore to level 2 at the top of your code before setting up everything else. Please give this a try and let me know the results.

0 Mark Hubelbank over 7 years ago in reply to Eddie LaCost

Intellectual 470 points

All the checks were done from the running program, not a debugger. For what it is worth, when attempting to issue a break and then look at the registers from the debugger, the values were also zero. I tried to set the vcore outside of the code supplied with the USB example but anything I did caused the USB function to fail. I looked at the code in the example doing the VCORE changes and it is a bit cryptic.

0 Eddie LaCost over 7 years ago in reply to Mark Hubelbank

TI__Mastermind 47505 points

Mark,

Can you provide a code snippet of how you are setting Vcore outside the USB example, which causes the USB function to fail?

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MSP430F5658: RTC reads zero after call to PMM_setVCore