Werner Almesberger werner at openmoko.org
Wed Apr 15 01:44:37 CEST 2009

NeilBrown wrote:
> So I cannot program the GTA02 to wake on either
> a shake or an double-tap, and these have to be programmed on different
> interrupt lines.

I have to admit that it was me who was pushing that "simplification".
For some reason, I didn't catch that you couldn't combine free fall
and click, so I thought it was fine to have only one interrupt :-(

> One area might be in reviewing a detailed design to look for
> details like this:

I think an open review process would be great. If I understand the
direction where Steve wants to take the hardware development process,
public reviews would in fact become a fairly natural thing to do.

>   - AUX button cannot wake from suspend (Though I don't know why this
>         is the case for GTA02 yet...)

Ah, it's because AUX switches between NAND and NOR. The status of this
"switch" is not latched by the CPU, so anytime you press or release
AUX, you interchange NOR and the memory used for NAND booting.

We can avoid touching this memory except when booting. Unfortunately,
also resume-from-suspend executes part of the boot sequence. So if
AUX is used as a wakeup source, there's a high risk that it will
"bounce" while you're somewhere in that critical section, which would
have largely unpredictable consequences.

- Werner

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