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LED Current on MetamotionC with Firmware 1.3.6

MichaelGMichaelG
in Hardware
I'm noticing that when I activate the LED using your iPhone app (eg Turn on Green) followed by Turn Off and then Disconnect that the current draw on the battery is around 300uA. Only reconnecting and perfoming a Soft Reset will restore it to the usual 17-22uA. I noted in the Firmware 1.3.6 post that one of the fixes was LED Idle Current. Given the results I am seeing, I'm not sure it's fixed.

Comments

  • EricEric
    Ok, we'll look into it.
  • MichaelGMichaelG
    A little more information regarding anomylous LED behaviour. Using LED patterns with rise/fall time of 0ms, a high of 10 seconds and a duration of 20 seconds at 31 for intensity, current consumption is steady around 1.2-1.3mA for Green and Blue and around 3mA for Red for the 10 seconds high time. However, halving this (setting intensity to 15) results in the current rapidly ramping up, hitting overload for my multimeter (6mA) and then droping off and starting over again, rampling up, hitting overload, repeat. Halving the intensity again (setting intensity to 7) results in around 100mA above the base load. I'm not sure why half intensity results in such eratic behaviour, but may give a clue as to the problem.
  • MattMatt
    @MichaelG

    There is a firmware release in final testing that resolves the idle current issue.

    Root cause was silicon errata on the SoC, where the timer used to generate PWM signals does not correctly shut off when it is stopped.  The new firmware implements a work around to completely shut it down.

    I'm not sure what to make of your secondary observations, when repeating your experiment on new firmware these were my results for On/Off current:
    Red Intensity 31: 4.7mA/20uA
    Red Intensity 16: 1.2mA/20uA
    Red Intensity 8: 500uA/20uA
  • EricEric
    A beta release with the current fix is available to try out.  Use MetaBase to update your firmware to 1.3.7.
  • MichaelGMichaelG
    Having tried the 1.3.7 firmware, it appears to have addressed the 300uA posted originally. I am aslo not seeing the Intesity issue when setting Intensity 15 for the LED, the current seems to be stable around 700uA. I'm using the color Green for my testing.
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