• Sorry for being that little clear: I don't have a MDBT42Q board. I want to define my own definition board, and I thought MDBT42Q.py was a good start...

    Indeed I do have a board with a low-frequency crystal (actually it is still in the mail) and I want to enable it so it is not sitting there wasted + to save some power.

    I have 2 nRF52832 boards I would like to use as beacons:

    I used the standard MDBT42Q.py definition file to build the firmware for the Holyot board.
    I would like to write a board definition file for the FEASYCOM that:

    • enables its MCU-external though board-embedded low-frequency crystal +
    • sets a pin to let the board enter DFU mode / hard reset mode.

    I did some power measurements on nRF51822 boards programmed as beacons (not nRF52832 boards though, not Espruino based) using the NORDIC Power Profiler Kit II, and I came out with this comparison chart:

    Low-Frequency Oscillator Average Current Consumption @ 3V
    External 32768 kHz crystal 7.85 uA
    Internal RC circuit 8.24 uA (14% more)

    Thus I expect to save about 14%. This result corroborates this discussion on Nordic DevZone Q&A.

    Once I successfully generate an optimised Esprino firmware for my FEASYCOM board, I would like to do the same comparison...

    I did some measurements on the Holyot board programmed as a beacon using Espruino and was impressed by its low power consumption already!

    However I also noticed little current spikes here and there in-between two broadcasting emissions (the board was sleeping?) that might be due (I have no clue though) to the use of the RC internal oscillator.

    This is why I would like to try the same code on the FEASYCOM board which Espruino firmware is built enabling its low-frequency crystal (+ redefining the reset pin to be able to exit the NRF.setAdvertising mode easily).

    • Regarding the builtin DC/DC converter, I need to understand how to enable it using Espruino?
    • Regarding the bootloader, I need to understand how to account for that new button pin definition?
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