My 32bits ATSAM node project

  • Hardware Contributor


    This is a project in progress. So I post here if I need to ask for some help (and I think this will be the case).

    First, thx to @tbowmo for his work on 32bit GW πŸ˜‰
    And thx to Sparkfun, Adafruit etc.. for all their work πŸ™‚

    I would like to introduce to you : M.and Ms Sam&LoraLip and their baby child πŸ˜† πŸ˜…
    A board with a 32bit Atmel Atsamd21e17 (128k, e18 is 256k) and Lora (Long range RFM95W, but there is also a nrf24 smd footprint), with Lipo Charger. And two proto childboard.

    Left top : M.&Ms Lip the mainboard
    Right top : W(H)eather childboard, nice sensors for meteo
    Left bottom : Adafruit Feather M0 ???
    Right bottom : Chi-Mote, (humm missing inspiration..) a childboard I have made for the Feather. For gesture and 3d control with rgb feedback. Sort of wiimote but smaller with Chi in this one πŸ™‚

    Specs a little bit below;

    So As you can see I have been inspired by Adafruit Feather M0. No advertisement here πŸ˜‰ It was out of stock so I assembled one. First, to be sure to have a 32bit board (atsam based) which works. And finally, because I wanted to have a simple lipo capable board. But that was not enough..more things.

    Briefly :

    • I keep lipo + usb from Adafruit (as it's a charger, so it's nice to have usb on this one). Usb can be used to upload sketch as native usb.
    • here it's 32pins TQFP ATSAMD21E16/17/18, I bought an E17 128k (on Adafruit, it's a nice big 44pins VQFN G18 family, first time for me, thx to my reflow). E17/18 cheaper compared to G18. If I would like to use L picopower family, I just need to swap 2-3pins.

    And I added:

    • footprint for usb filtering on +5v and shield
    • footprint for fuse
    • atsha204a
    • eeprom in case
    • rgb led
    • footprint for Nrf24 smd, RFM95W (not received yet), RFM69HCW (pincompatible with RFM95W if I'm right)
    • for RFM95W, wire style antenna or connector
    • MYSX connector (maybe I will reduce it)

    I have made two child boards

    • Weather optional (or not!) sensors : opt3001 for light, veml6070 for UV, SI7021 temperature/humidity, BME 280 temperature/humidity/pressure (in case I use this one I don't need si7021 of course), there is also AS3935 for Lightning detection. + switchable battery voltage sensor
    • For the mote : RGB led, APDS9960 for proximity&gesture, 6DOF LSM6DS3 (6DOF is enough for what I want to do but maybe a better/expensive MEMS could be fun...)

    Ok you really are cool guys if you are still reading. Now the pics:

    Nrf radio style
    Long range RFM95 style
    Weather child board on mainboard
    Assembled (no radio soldered, still doing basic tests), weather not assembled
    Chi-Mote for MYSX connector (I will add an IR led as I have enough space, more fun)

    And Chi-Mote for Feather, on top of it πŸ™‚ no radio soldered yet.
    With a small lipo and humm..wireless charging, more Chi πŸ‘Š

    And a very short video of my kungfu gizmo πŸ˜„ Gesture part is buggy for the moment so not activated and on the 6dof I only use single/double tap. Connected on a nano. but fixed on the wall, or few mobile in the house, very cool.

    Current status:

    • the feather I assembled works ok. bootloader ok, and blinkled in arduino ide ok πŸ™‚
    • weather not tested yet, Chi-mote, all is good πŸ™‚ except gesture (I suspect power+infinite loop in lib!). Add an ir led
    • my mainboard: sam-ba bootloader for ATSAMD21E17 well sent with jtag in Atmel studio, but I get a no device connected on comport in arduino. I am investigating if it comes from boards.txt ..
      Few things to improve on mapping part

    Certainly more things to say..but that's ok for today! I'm enough happy.
    Thx for you interest and feedback.
    See you soon πŸ™‚

  • Hardware Contributor

    Amazing work !!!

  • Contest Winner

    @scalz I'm impressed. It's people like you who make the difference!

  • Very good job ! I will be happy when I will able to do 10% of your work πŸ˜‰

  • Hardware Contributor

    thx guys, that's really kind comments πŸ™‚

    I hope to fix my small bug about upload in arduino ide, to share then. I don't know yet where it comes from.. I need to investigate as it's a little bit different compared to Arduino Zero because I'm using a "smaller" pincount chip so maybe it needs some tune.
    In other hand, I am already dreaming of a @Tekka's atsam ota bootloader lol ! few second upload with jlink with only two pins and then ota. But in other hand it's nice when usb is there, to have the native usb in ide so I really need to fix this (certainly software related..).

    Tests I did to try to understand:

    • with first homemade board ATSAMD21G: upload of adafruit bootloader (which I think is derived from the Zero or maybe the same). My device is then detected in Windows as an Adafruit device Virtual com port. In ide, I choose adafruit Feather board, upload sketch. Yeah! If I choose Zero board, it uploads too! And in Windows, my device is then detected as a Zero device. I can do inverse. So it's interchangeable but not recommanded because you need to take care about io mapping of boards, variant cpp...
    • with my second board, ATSAMD21E : I use bossa bootloader from atmel dedicated for this chip, BOSSA programming device comport well detected in windows on COM14 for instance, but I get a "no device found on comport14" when I try to upload in arduino ide..I tried with others bootloader, still the same..of course!
      If you are curious, Bossa is sort of avrdude which is included in arduino ide for atsam. I have multiple programmer, but for the moment I am using a Segger OB which is the same as Atmel ICE (I had luck to find this programmer, genuine, discounted!)

  • Hardware Contributor

    wew! I have just got the blink led sketch uploaded from arduino ide on my custom D21E. great! now I need to check my board and io mapping. cool cool πŸ™‚

  • Hardware Contributor

    cool I have my Chi mote working on my custom board, after few changes in libs regarding atsam πŸ™‚
    Next step, mysensors libs and I can't wait to receive my lora module to give a try. I have nrf smd footprint but no more in stock, so impatient that I'm thinking to unsolder one on another board πŸ˜†

  • Admin


    Cool project! πŸ™‚

    But RFM95W is not supported by MySensors yet? (at least I think that it doesn't.. Haven't seen a git commit for it in the library). So are you going to use another library for that module?

  • Hardware Contributor

    @tbowmo thx πŸ™‚

    I'm discovering the joy of new chip πŸ™‚ and the stuff about sam bootloader, arduinocore, board/pin def. I have not digged so much but still good to know how things are connected.
    Hopefully I found a bootloader+board def which fits almost with my pinout, but spi part which is not in same order. Cool this story of configurable sercoms..but that still needs to adapt a little bit pins define in variants...does I understand right? Sometimes it's very confusing all this stuff of pins define between boards etc..

    I have not tested the spi part yet, but very soon I will wire at least rfm69 and nrf. I have not received my Lora. I have looked at multiple libs, don't know yet which one. My first choice may be not radiohead, I will try it sure, but I would like something "standalone". I will start with basic examples! and then "standalone" will be easier to add to mysensors transport stuff I guess (my lazy way..) But don't know yet when πŸ˜• I would like to finish what I have started on rfm69 part.

  • Admin


    Do the RFM95 use the same footprint as RFM69?

    About the SPI, you might need to hack the standard arduino SPI driver a bit (I have done this for the GW module..), depending on how you have wired your sercom/SPI unit..

  • Hardware Contributor

    yes I have found where to hack spi pins...will give a try this evening I think. If I can't get it to work may I ask you ? πŸ™‚

    To resume a little bit about rfm, there are:

    • RFM69HW : High power version (best known version)
    • RFM69W : non-high Power version, pincompatible with RFM69HW
    • RFM69CW : other non-high power version too, but not pincompatible with those above W
    • RFM69HCW : High Power version again. But we could think this one is pincompatible with the simple CW. That's not the case! This one is pincompatible with RFM95W!

    All these RFM69 are software compatible. Very confusing, isn't it? but more options!
    As you can see, I have made this board for long range fun, and personal challenge πŸ™‚ With RFM69 high power version and RFM95 (outdoor, and that's why there is the lipo charger maybe basic solar app) .
    But in case, I would like to have a lower power radio, I added nrf footprint. I couldn't add another low power RFM69! I will certainly have two version of this board: one long range, another RFM69CW+nrf maybe without lipo charger this time..

  • Hardware Contributor

    hi. I was just thinking that I didn't give news about my mux!
    in case, I guess you already know it, but that helped me so I share:
    I tried the howto for i2c too. worked nice.
    so no need to hack the lib in my case. (even if I have rerouted my board to fit mattair pindefinition which I prefer because "real" pin number match to pin number in arduino..matter of taste).
    Perhaps hacking libs could give a little bit more freedom but that's already pretty flexible like this, cool πŸ™‚
    I have not had lot of time for my lora modules yet, still on my desk, pfff 😞

  • Contest Winner

    Amazing work again. I really love the name Chi-mote πŸ˜‰

  • Hardware Contributor

    @TheoL thx πŸ˜‰

    I am really beginning to like this little 32bit chip.. mux flexibility, enough memory, the price. Even if I was planning to use my jtag smd pins with pogo, usb cdc is cool for direct connection programming and uploading is really fast!

    the only downside is, I was aware, it require to make changes in sensors libs , to add constructors for platforms defines+modifying a little bit our common wire, spi, interrupt functions. For testings purpose it's ok, but I should fork these libs to add my much work!!! for the moment I have tested/modified only few libs like SI7021, ambiant light sensors, apds9960, 9930, mems, neopixel etc., still local..

    I will now post my design files soon for those who would like to try πŸ˜‰ I just need to make few tests/minor decisions on my design.

    When I see those price of released lora, sure could be better but I'm happy with my board. I thought that I could try to make my own rfm95 circuit onboard, could be cheaper and a little bit smaller. But generally, I prefer to use a FCC compliant module, especially for lora...and so I can have footprint for an other radio, more modular, who said useless lol!

  • Admin


    Most of these sensors that you mention (si7021 etc) they are I2C, so only the base I2C driver needs to be adapted, so what changes are necessary for (for example) SI7021 to get working on the atsamd?

  • Hardware Contributor

    @tbowmo you're right, it's because of a wrong mapping!! If I only use something like Wire.begin(sda,scl) it didn't worked well for me. Of course this could be fixed in variant, sercom.. etc but I didn't want to change this or create mine (I prefer to stick an existing/well updated one). So the only thing I need, to "remap" my pins, is :

    #include "wiring_private.h" // pinPeripheral() function
    #if defined(MY_ATSAMBOARD)
        TwoWire newWire(&sercom3, 22, 23);

    And in setup, or in libs..

    #if defined(MY_ATSAMBOARD)
        // Assign pins 13 & 11 to SERCOM functionality
        pinPeripheral(22, PIO_SERCOM);
        pinPeripheral(23, PIO_SERCOM);

    And then I need to use my newWire object instead of common Wire.
    rough example, not beautiful, that should be better done I know..but it's rough test and for my bad mapping. When remapped to the right pindef boards, that should work like it should do..
    Hum..I will give another try to Wire.begin(x,y) to see, you make me not sure now...πŸ˜•
    In other hand, how libs manage if someone want to play with another i2c? Wire function and begin() are hardcoded in libs, so it use default i2c bus mapping...

  • Admin


    I've made "local" copies of SPI / TwoWire libraries (Local as in mysensors specific), which are added to the SAMD GW hw profile in Arduino.

    So people just choose the correct board, and everything is setup for them πŸ™‚

  • Hardware Contributor

    @tbowmo cool, thx πŸ™‚ I forgot that's included in mysensors git! I will look at your work and diffcheck to see your changes. I will try this for this rev at least even if it's working with ugly cheat πŸ˜‰

    My next rev follow mattairtech board. So I won't need this, and no arduinocore files versioncheck . I let others doing this. So I will just choose the right hardware in ide and that should work like a Zero. This is actually what I am doing but I am cheating to fix my wrong mapping.

    Thx for your feedbacks. I agree with you, each test/learning session takes a lot of time but I will try your way and report; the way I started to look but found a trick πŸ™‚

  • Hardware Contributor

    cool, finally I have made my board definition 😊
    maybe I was missing something during my previous attempt as it was not so hard..
    works nice like you said πŸ˜‰
    look at this upload speed!! not a big upload (just an example test sketch) but crazy cool πŸ˜ƒ

    thx πŸ‘

  • Contest Winner

    Very interesting thread!
    I hope arduino project (and any child projects) will move to more fast hardware in near future!

  • Hardware Contributor

    @Koresh oops didn't see your answer, thx seriously I'm very glad πŸ™‚ but there are still few things which are choking my eyes. That's why this one is not released yet. arghh, not enough time!

  • What the current status of your 32bit project??
    Also what work have you done with the RFM95 radio and it integration into MySensor 2.0b??
    I'm looking at doing some work with the RFM95 and do not want to duplicate work that may already been done or started.....


  • Hardware Contributor

    on my desk lol I have not made a box for it yet! comm is working with basic libs examples. and I'm playing with my custom Zero and sensors. And I will be more tempted when I will have received my usb dongle pcb πŸ™‚
    so you can do it if you want. like I said I will look at it bit later, if not already integrated πŸ˜‰
    not a big thing that mostly need to do the transport layer. time I don't have for the moment..arghh

  • Hardware Contributor


    Hi. Where did you buy the ATSAMD21Exx MCU s ? I'm more interested about the ATSAMD21E16 variant.

  • Admin


    They are available from (at least, that's where I source them from, when making prototypes)

  • @scalz Hi,
    i know its been long time but stil l!!!
    Can u please explain how it got resolved?

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