Avatar for mikewop


Member since Mar 2014 • Last active Nov 2014
  • 1 conversations

Most recent activity

  • in Interfacing
    Avatar for mikewop


    Personally I've always wanted to make a PCB with a whole bunch of
    snap-out adaptors for various modules...

    That's a great idea. I personally find that they key part in that is the "universal connector/port" design if you want to attach multiple modules. Probably would be good to stick with one that is already out there ....

    The "MicroBus" seems pretty versatile, but the footprint is kind of big and doesn't use a regular connector.
    UEXT seems versatile too, but might be lacking dedicated GPIO/Analog/INT/PWM pins.
    Gadgeteer defines different "Port Types" for the 10-pin connector to get around the limited number of pins.
    So there isn't really one out there that can do it all, Gadgeteer comes pretty close I think, but the connector and the cables are just a pain to work with (not 0.1" compatible) ...

  • in General
    Avatar for mikewop

    Hi Ollie,

    the Espruino has a linear Voltage regulator (MIC5205) so since the electronics need 3.3V as power supply, the excess is converted to heat in the voltage regulator. Assuming your whole setup takes about 200mA current, for a 9V battery this means 5.7V * 0.2A = 1140mW = 1.14W of heat is being generated by the voltage regulator (9V - 3.3V = 5.7 V).
    Since it's mounted on the PCB without really a heat sink, I am guessing it gets really hot and goes into thermal shutdown (The MIC5205 has an internal thermal protection, see the datasheet: http://www.micrel.com/_PDF/mic5205.pdf There are also some more detailed thermal calculations on pages 8/9 of the datasheet).

    At least that is my guess as to what is happening. The other scenario is that your battery is already too weak to supply the current for the Espruino + BT + CC300 module, but you could easily measure that by checking the battery voltage when you have everything connected.

    I would probably use a rechargeable battery (LiPo) or 3 NiMh cells to power the Espruino. A 9V battery has inherently a pretty low energy density. You could also use a high-efficiency switching regulator circuit to power the Espruino if you really have to use 9V batteries.
    Hope that helps,

  • in General
    Avatar for mikewop

    Did you see this note (from here: http://www.espruino.com/Other+Boards):

    "Note: This board is more difficult to connect to. You need to power
    up the board without 'USB USER' plugged in, and then plug in USB
    later. If you subsequently reset the board, you'll need to unplug USB
    and plug it back in."

    You need to use the "other" USB connector (USB_USER) and not the one you used to upload the Espruino software.
    Maybe that is the issue you are running into?
    But reading your note again, you probably already tried that.

  • in Interfacing
    Avatar for mikewop

    Did you ever figure this out?
    Looking at your mapping table and at http://www.espruino.com/HD44780 it seems that:
    RS = A0 (Espruino) = D2 (Maple)
    EN = A1 (Espruino) = D3 (Maple)

    So with that the constructor would have to be:
    var lcd = require("HD44780").connect(D2,D3,D15,D16,D17,D18);

    (Also, I am not sure if you just could use the Espruino pin names directly or if the Maple build remaps those to the Maple pin names - I assume so since you probably thought of that already).


  • in General
    Avatar for mikewop

    Hello user6350,
    did you ever succeed in getting the SDCard to work on STM32F4DISCOVERY?
    I have a few of these boards laying around and want to make them useful by using the Espruino firmware on them...

  • in General
    Avatar for mikewop

    It might be a python or python version issue:

  • in JavaScript
    Avatar for mikewop

    I would also be interested in how you got the toolchain set up on your Mac and how you get the executable onto the board from the Mac.

  • in Interfacing
    Avatar for mikewop

    Sorry, ignore this post, I had posted to wrong thread :(

  • in General
    Avatar for mikewop

    I would also like to see an Espruino board with more "headroom", that is one of the reasons why I haven't bought one yet. The STM32F103RGT6 is about $3.50 more in small quantities on mouser.com, I'd gladly pay more for a board that has some room to grow, since I am planning to use Ethernet/Wifi and nRF24L01+ connectivity.

  • in Interfacing
    Avatar for mikewop

    @conor Thanks for posting this code! Great you got it to work (at least one way).
    How are you powering the nRF24L01 module on the Espruino?
    Are you using a module with PA?
    Maybe the module doesn't get enough power from the Espruino in transmit mode.