Espruino on E73-2G4M04S-52832

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  • Hi folks, I just got my hands on this very low-cost module and now eagerly awaiting some sweet breakout PCB's from Oshpark. Initially was going to tinker around with this and Arduino but decided to look into Espruino!

    I am relatively new in electronics and would like some direction. My assumption is that other than physical layout, the process of flashing espruino on this board would be similar to the official MDBT42Q boards?

    pin P.00/XL1 is not listed on the module (E73-2G4M04S-52832) official website, and there are pins labeled DEC2, DEC3 that aren't listed on MDBT42Q , are these pins the same pins but labeled differently? How could I replicate the function of this pin on a E73-2G4M04S module?

    Official page:­ews.aspx?id=243
    Datasheet (PDF):­d=243

    Thank you!

  • I imagine you can just program it the same way as any nRF52 with the SWD/SCLK pins.

    It looks like P00/01 aren't available because there is an on-module low-speed oscillator, which is quite a nice addition (you'd have to build your own firmware to take advantage of that though). DEC2/3 are for the switching power supply, but that's actually not such a big deal and I'd just leave it off.

    Just to add though, looking at the price you may find the Raytac MDBT42Q is actually the same price or cheaper - and obviously firmware for it 'just works' :)

  • Thank you! Will have to look into building a custom fw, what’s the level of difficulty?

    I have a Raytac module too, these just came in at $3/module on a promotion - was hard to pass up.

  • It's not hard really (especially if you're running or have access to a Linux machine) - details here:­b/master/

    There are plenty of threads here on tweaking the build for different things as well.

  • Thank you for the guidance kind Sir!

  • Did you ever get around this?

    I am looking at the PineTime that is also equiped with a nRF52832

  • Yeah, aliexpress recommendations and sales are harmful :) BTW just the bare E73 "module" is about as big as Gordon's MDBT42Q breakout (see the attached picture).

    I was just playing with this yesterday, got the "devkit" variant on 11.11 sale... By default the flash was locked, so you you need an SWD programmer to unlock and program it! Couldn't find real documentation, just this pastebin with some pinout info.
    First try: just flashed the MDBT42's flash, and it did work :)
    Second try: here is a board file based on the MDBT42Q:­uff/blob/master/boards/ Only set up the LEDs and buttons, did not do anything about the low frequency oscillator.

    As for the Pinetime -> It's "just" an Y7 smartwatch. One of numerous nRF52832 watches. Afaik you need an SWD programmer, and you need to open the back to access the SWD pins. But the back is glued, so it won't be water proof after opening it. Maybe not the best option for "hacking" it...
    But probably the MDBT42Q firmware should just work as a starting point...
    This thread has a lot of info on various nRF52832 based watches / bands.

    1 Attachment

    • e73_mdbt42q.jpg
  • I am looking at the PineTime that is also equiped with a nRF52832

    All of nrf52832 watches are in a way very similar, however if you don't want take apart each piece it is worth focusing on ones with unlocked bootloader which can be updated over bluetooth. Then you can get two same devices, one for taking apart and debugging via SWD as a devkit and second for stable code. The selection of suitable nrf52832 fitness trackers and watches to start with is relatively good now. It is limited but depends now more on price, size, form factor (how many buttons, which sensors). Check my list here, but there are more. Unless PineTime starts selling their watch with unlocked bootloader it is not worth preferring it to any other nrf52832 watch IMO. The Y7 'devkit' is reported by people to be locked so it needs SWD to erase and unlock it as a first thing you need to do.

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Espruino on E73-2G4M04S-52832

Posted by Avatar for user92454 @user92454