tom dunigan / Mbed 2 deprecated driftrtc

LPC1768 RTC frequency check with WDT. Compare RTC against MCU's microsecond Timer.

Dependencies:   mbed

Check LPC1768 RTC crystal frequency using WDT. Measure with MCU's microsecond Timer. The MCU's crystal may be off a bit as well. I measured the RTC frequency error at 22 ppm. The spec for the RTC crystal is 20 ppm. Using NTP and a GPS, I had measured the MCU's crystal frequency error at -2 ppm.

Frequency measurements for other MCU/RTC cyrstals at

https://github.com/manitou48/crystals/blob/master/crystals.txt

mbed.bld@0:11cc29f22037, 2015-11-16 (annotated)

Committer:
manitou
Date:
Mon Nov 16 16:56:32 2015 +0000
Revision:
0:11cc29f22037
LPC1768 RTC freq check with WDT

Who changed what in which revision?

UserRevisionLine numberNew contents of line
manitou 0:11cc29f22037 1 http://mbed.org/users/mbed_official/code/mbed/builds/da0ca467f8b5