MMR falls back to deep sleep...


We have a bunch of mmr boards - and for some reason, they fall back to the sleep state in which they were shipped.
This is an issue, as we use them fully enclosed with an attached qi charger board (attached to the 5v input)

Some times they just “disappear”, and we can only wake them by opening the case, and pressing the button.

As I read the datasheet, the 5v pad is the same as Vusb, but I’m starting to think that might not be the case?



  • @NIVO

    The process of putting a device to sleep is fairly complex in firmware, I would be quite surprised if the devices are entering that exact state. Note also that on the MMR model, attaching the 5v source would also be a trigger to wake the device from sleep.

    The 5V pad is in fact the same as Vusb. We've changed company policy and will be posting schematics in the next day or two if you would like to look for yourself. Check on the documentation page on our website.

    Given the presence of Qi charging, I would expect the possibility of a power fault triggering latchup or some other hardware fault. Note that the full scale charge current is 90mA, and will scale down to approximately 20mA before shutting off. The Qi controller must be able to scale down current to these levels without exceeding the minimum and maximum voltage ratings of the battery charger. Qi chargers typically operate in the 2.5-5W range which is quite a lot more than 90mA, and is the first place that I would look.


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