Backup battery discharged -> GTA01 and GTA02 dead

Werner Almesberger werner at
Sat Jul 19 16:28:10 CEST 2008

Rod Whitby wrote:
>  Is there a test point on the GTA02 I can  
> look at to debug whether the PMU is powering up the device or not?

You could monitor nRESET. It rises to ~3.3V when the PMU thinks power
is stable enough to allow the system to leave reset.

In GTA02, if held upright, nRESET is on the rightmost test point above
the debug connector, under the debug cable (if attached). I would
recommend disconnecting the debug board when monitoring nRESET, as it
may change the level of nRESET.

You can see the test point assignment here:

The map under the LCM corresponds to the test points around the
debug connector.

This image shows how nRESET behaves:

The noisy blue curve is nRESET, the yellow one is the SYS voltage.

- Werner

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