Guide/Tutorial/Reference about Expansion Board

  • Here is a long guide/tutorial/reference about all Expansion Board models :

    Thanks to Ricardo Retsos.

    "Using Expansion Board" has :

    • hints & tips collected from some years of experience, Pycom forum, etc;
    • detailed descriptions of features, mini-jumpers, etc;
    • list of documentation from Pycom and community;
    • many comparisons between the Expansion Board models;
    • tutorial about installing firmware on Expansion Board v3.x;
    • example source code to access user LED, user button, microSD slot, read battery voltage, etc;
    • energy consumption measurements of all Expansion Board models in active/light sleep/deep sleep, with USB power supply and battery power;
    • voltage measurements with USB power supply and battery power.

    For example, tests with Expansion Board v3.1 with WiPy3 in :

    • deep sleep mode, power from battery (Vbat = 3,61-3,66 V) :
      • 34 uA with only TX/RX mini-jumpers;
      • 102 uA with all mini-jumpers;
      • 183 uA with 8GB Sandisk UHS-I uSD and all mini-jumpers;
      • 160 uA with 16GB Toshiba M203 UHS-I uSD and all mini-jumpers;
      • 692 uA with 32GB Samsung Evo UHS-I uSD and all mini-jumpers.
        So :
      • the LED mini-jumpers adds 68 uA;
      • microSD card, just inserted, adds 58-590 uA, depending on the uSD card (not only the capacity).
    • active mode, it seems a 'feature' (or bug ?) when using TX/RX mini-jumpers and battery supply (3.61-3.66 V) :
      • 34.5-35.0 ma without mini-jumpers;
      • 68.8-69.4 ma with only TX/RX mini-jumpers
      • 69.6-70.2 ma will all mini-jumpers.
        This is a 33.8-34.9 mA increase.
        But when using USB power (Vusb = 5.06-5.08 V), this issue doesn't happen, i = 43-44 mA with any mini-jumpers configuration.

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