Computing stuff tied to the physical world

Clock Plug v1

In AVR, Hardware on Sep 20, 2009 at 00:01

The Clock Plug adds a real-time clock to a JeeNode:


A demo for setting it and reading it out follows:

Picture 2.png

Unfortunately, there seems to be a problem with it – it does not start up reliably, and connecting the backup battery makes it stop?

Oh, wait – the DS1307 is specified for a 4.5 .. 5.5V power supply, and I’m driving it from the 3.3V line! And yes, sure enough, it works fine when powered from 5V.


Time to look for another chip. Ah, looks like there is a pin-compatible one which does work at 3.3V – here’s a post from someone who fell into the same trap.

Update – the DS1340Z works fine, see this followup post.

  1. You can add a step-up DC/DC converter. Maxim and Linear have some DC/DC converters with high-effiency.

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