lpcware

RTC Battery Backup

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by mike31416 on Thu Jun 09 05:25:39 MST 2011
Hi,

The LPCXpresso Base Board has provisions for a coin cell to backup the RTC. Looking at the base board schematic the battery would also power the base board unless J3 is removed. That helps, but the battery is also connect to J4-28 which is the 3.3V input to the LPCXpresso LPC1768 in addition to VBAT on J4-3.

I think if D2 were removed, then the battery would only be connected to VBAT on J4-3. I am not sure why D2 is there unless they expected to power the LPC1768 with the coin battery. The battery will not last very long doing that.

Mike

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