Userspace Arduino

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Development Blogs for the Userspace Arduino project:

This page documents research on creating a userspace executable using the wiring and Processing language used with Arduino.

Getting Started


git clone


BeagleBone Black

~$ wget
~$ sudo tar -C / -xzf angstrom-2011.03-x86_64-linux-armv7a-linux-gnueabi-toolchain.tar.bz2
~$ export PATH=/usr/local/angstrom/arm/bin:$PATH
~$ export CROSS_COMPILE=arm-angstrom-linux-gnueabi-


  • todo

Raspberry Pi

  • todo

Running a demo

example of HelloWorldUserspace:

cd Userspace-Arduino/arduino-makefile/examples/HelloWorldUserspace
  • A binary HelloWorldUserspace.elf should be created in a directory build-userspace
  • Copy the binary to the Beaglebone Black and execute using the "make upload" command

Using send_exec

  • send-exec is a nice little upload and execute script, which has now been integrated with the Arduino-Userspace repository. It uses the scp protocol to copy binaries to the Beaglebone Black over USB ethernet and ssh to execute it.
  • To use it, simply do a
make upload 

in the same directory where the makefile is located for the respective examples.

  • If you want to avoid a password prompt, you can set-up the ssh keys for the Beaglebone Black:
cd ~/.ssh
ssh-keygen -t dsa #set password or you can leave it blank
ssh-copy-id -i ~/.ssh/ root@$ # replace by your public key file if some other name is given
ssh root@ # login and enter password once

Here after, you won't be prompted for a password from this machine

Boards Supported

Beaglebone Black

Initial development is being done with the Beaglebone Black and the Bacon_Cape

  • if you have your beaglebone black loaded with a firmware image older that 07.11.2013, you will need copy the Bacon Cape dtbo file on to your beaglebone black
~# scp ~/Downloads/BB-BONE-BACONE-00A0.dtbo root@
Arduino Pin BBB Header Pin Function Alternate Function
0 P9_11 UART (RXD)
1 P9_13 UART (TXD)
2 P9_15 GPIO
3 P9_14 PWM
4 P9_12 GPIO
5 P9_16 PWM
6 P9_42 PWM
7 P8_19 GPIO PWM
8 P9_19 I2C (SCL)
9 P9_20 I2C (SDA)
10 P9_17 GPIO SPI_CS0
12 P9_21 SPI_MISO
13 P9_22 GPIO SCK
18 P9_33 AIN4
19 P9_35 AIN6
20 P9_36 AIN5
21 P9_37 AIN2
22 P9_38 AIN3
23 P9_39 AIN0
24 P9_40 AIN1


  • Initial support started
  • Need Lure accessory board for testing

Raspberry Pi

Transfer Options


  • GNU Netcat networking tool
  • Can create a connection using nc -w 1 1114 < on the server (in this case the machine running the Energia IDE), and nc -lp 1114 > on the Beaglebone. 1114 is a random port number which has to be the same on client as well as server side.
  • Some issue with sending .bin files directly. Mostly it was with how the file ends, not sure. So need to zip the file.
  • Requires no authentication
  • A script will be needed to listen on a particular port on the BBB for any incoming connections which will receive, unzip and execute the code.


  • Needs ssh and sftp installed
  • Need to configure keys initially. Works without user authentication after that
  • Code to upload and execute binary here :
  • To do :
    • Create Sketchbook folder
    • Fetch output if any, display it in the serial monitor

Emulating the Arduino bootloader

  • The Arduino Bootloader uses a protocol similar to STK500v1 (over UART, though)
  • One way to program (copy) the binaries would be to emulate the protocol on the bone over USB gadget and use AVRDude on the IDE side
  • However this would be cumbersome, since the protocol was designed to write bytes to flash memory, not copy files.
  • Energia uses mspdebug to flash the MSP430 using a serialized version of JTAG called Spy-Bi-Wire (SBW).
  • File transfer protocols over serial like XMODEM and ZMODEM could be explored for an easier and more compatible option to Upload the binaries.
  • Install the lrzsz package on both the host (PC) and the client (Beaglebone):
apt-get install lrzsz
  • Connect the Beaglebone via USB and determine the port (for e.g. /dev/ttyUSB1). Once the OS is booted up, start the transfer:
sz -vv -b filename.bin < /dev/ttyUSB1 > /dev/ttyUSB1

HTTP post

  • Send executable over port 80
  • On BBB, listen for any uploads and execute them

Action List and Issues

  • The Arduino 1.5 IDE has better support for arbitrary architectures than the Energia fork of Arduino. This could help since the architecture specific stuff has been moved to config files. Further investigation is needed. Should the Userspace implementation forked directly out of the Arduino IDE or should the current implementation continue?
  • For development beyond the GSOC period, an option to get this upstream needs to be considered.
  • The BBB needs a separate FTDI cable for serial ports. However, a /dev/ttyACM port is available over USB. It can be used for uploading via the normal bootloader way. After the upload, it can be used for serial read/write to the host (PC).
  • A single protocol to tackle uploading via USB and ethernet and may not be feasible. Networking over USB is pretty unreliable and tough for newbies to get working. For ethernet upload, several of the above options can be considered. For USB, a simple bootloader emulator will do.