A problem setting the Lemur RTC date

NETMF & Gadgeteer
#1

Hi guys.
I have a problem setting the Lemur RTC date. After deploying code containing method RealTimeClock.SetDateTime(any_date) my device freezes. After that it’s not possible to deploy code anymore, no answer on ping.

Output after deploying a code:
[em]Looking for a device on transport 'USB’
Starting device deployment…
Iteration 0
Opening port \?\usb#vid_1b9f&pid_0102#7&159e09fd&0&1#{d32d1d64-963d-463e-874a-8ec8c8082cbf}
Attaching debugger engine…[/em]

To make Lemur accessible again I have to reload firmware. Maybe there is a better way…
Same behavior occurs if calling method RealTimeClock.SetAlarm.

Method RealTimeClock.GetDateTime() causes no problem, but the time doesn’t change. It’s constant 01/01/1980 00:00:00

while (true)
{
    Thread.Sleep(2000);
    Debug.Print(RealTimeClock.GetDateTime().ToString());
}

Am I doing anything wrong? Is it possible that RTC on STM32 is somehow damaged?

NETMF v4.3
Lemur firmware 4.3.8.1

Thanks.

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#2

Lemur doesn’t appear to have the RTC caps and crystal, sorry. That would be why it hangs, it’s trying to set the RTC but that isn’t oscillating and fails.

#3

@ Brett - thank you, I see now. I looked into schematic and there is no crystal on pins PC14, PC15. Now it makes sense. But then the Lemur spec is little bit confusing.

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#4

yes, agreed ! Lemur itself has the ability if you wanted to bodge it up, as the G30 supports it. But yeah, GHI, can you update the product page for the Lemur to remove that?

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#5

@ Brett - For some reason the note about the crystal being required didn’t make it over from the G30 specifications. It’s been added to the FEZ Lemur specifications now.

#6

@ John, so there’s a footprint on the Lemur for the crystal? And I guess since you (only) need the crystal, the capacitors already in-place? If not, I would prefer the note to reflect that it’s non-trivial to get that to work on a Lemur

#7

@ Brett - No footprint, but the pins are exposed on the headers as GPIO pins. Capacitors are also needed. The note was expanded.

1 Like