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RTC functionality on Panda


#1

Is there any reason why the RTCX1 (16) and RTCX2 (18) pins arent brought out to pads or something, that way by adding a xtal, the panda could have an RTC, or am I missing something


#2

The 32khz crystal is very sensitive to noise. Bringing the signals to the header and then adding crystal externally wouldn’t help since it will probably not work due to longer traces and surrounding noise.


#3

ok, so you would have to waste real estate by leaving a no fit gap next to processor, for xtal and caps, but if I did my own board would it work, or is the rtc functionality only for the usbizi 144 parts, the pins are ther on the 100.


#4

Yes the RTC works fine on USBizi100 but we took the RTC crystal out for the “economical” version of FEZ.

If you are very good at soldering, you can wire the crystal right to the pins on the processor and it will work, do not forget the 3V battery.


#5

cheers gus,
what I need the rtc is for an alarm capability out of hibernate, im trying to cut down on the power budget, shurely in hibernate I dont need the battery


#6

I didn’t mean battery for power, but you need a small battery on VBAT pin to keep RTC running when system is off.