embedded-trainings-2020

Material for the beginner and advanced workshops of Oxidize Global (15.07.2020).

TODO add license text (from commit 1?)

Required hardware

• nRF52840 Development Kit (DK)
• nRF52840 Dongle
• 2 micro-USB cables
• 2 available USB-A ports on your laptop / PC (you can use a USB hub if you don't have enough ports)

Checking the hardware

nRF52840 Dongle

Connect the Dongle to your PC/laptop. Its red LED should start oscillating in intensity. The device will also show up as:

Windows: a USB Serial Device (COM port) in the Device Manager under the Ports section

Linux: a USB device under lsusb. The device will have a VID of 0x1915 and a PID of 0x521f -- the 0x prefix will be omitted in the output of lsusb:

$ lsusb
(..)
Bus 001 Device 023: ID 1915:521f Nordic Semiconductor ASA 4-Port USB 2.0 Hub

The device will also show up in the /dev directory as a ttyACM device:

$ ls /dev/ttyACM*
/dev/ttyACM0

macOS: a usb device when executing ioreg -p IOUSB -b -n "Open DFU Bootloader". The device will have a vendor ID ("idVendor") of 6421 and a product ID ("idProduct") of 21023:

$ ioreg -p IOUSB -b -n "Open DFU Bootloader"
(...)
| +-o Open DFU Bootloader@14300000  <class AppleUSBDevice, id 0x100005d5b, registered, matched, ac$
  |     {
  |       (...)
  |       "idProduct" = 21023
  |       (...)
  |       "USB Product Name" = "Open DFU Bootloader"
  |       (...)
  |       "USB Vendor Name" = "Nordic Semiconductor"
  |       "idVendor" = 6421
  |       (...)
  |       USB Serial Number" = "CA1781C8A1EE"
  |       (...)
  |     }
  |

The device will show up in the /dev directory as tty.usbmodem<USB Serial Number>:

$ ls /dev/tty.usbmodem*
/dev/tty.usbmodemCA1781C8A1EE1

nRF52840 Development Kit (DK)

Connect one end of a micro USB cable to the USB connector J2 of the board and the other end to your PC. After connecting the DK to your PC/laptop it will show up as:

Windows: a removable USB flash drive (named JLINK) and also as a USB Serial Device (COM port) in the Device Manager under the Ports section

Linux: a USB device under lsusb. The device will have a VID of 0x1366 and a PID of 0x1015 -- the 0x prefix will be omitted in the output of lsusb:

$ lsusb
(..)
Bus 001 Device 014: ID 1366:1015 SEGGER 4-Port USB 2.0 Hub

The device will also show up in the /dev directory as a ttyACM device:

$ ls /dev/ttyACM*
/dev/ttyACM0

macOS: a removable USB flash drive (named JLINK) in Finder and also a USB device named "J-Link" when executing ioreg -p IOUSB -b -n "J-Link".

$ ioreg -p IOUSB -b -n "J-Link"
(...)
  | +-o J-Link@14300000  <class AppleUSBDevice, id 0x10000606a, registered, matched, active, busy 0 $
  |     {
  |       (...)
  |       "idProduct" = 4117
  |       (...)
  |       "USB Product Name" = "J-Link"
  |       (...)
  |       "USB Vendor Name" = "SEGGER"
  |       "idVendor" = 4966
  |       (...)
  |       "USB Serial Number" = "000683420803"
  |       (...)
  |     }
  |

The device will also show up in the /dev directory as tty.usbmodem<USB Serial Number>:

$ ls /dev/tty.usbmodem*
/dev/tty.usbmodem0006834208031

The board has several switches to configure its behavior. The out of the box configuration is the one we want. If the above instructions didn't work for you, check the position of the on-board switches:

These directions assume you are holding the board "horizontally" with components (switches and button) facing up. In this horizontal position you'll find one USB connector (J2) on the left edge, another USB connector (J3) on the bottom edge and 4 buttons on the bottom right corner.

• Switch SW8, on the bottom edge left corner, is set to the ON position; this is the left position of the two possible positions
• Switch SW9, to the right the left edge USB connector (J2), is set to the VDD position; this is the center position of the three possible positions

Installation instructions

Base Rust installation

Go to https://rustup.rs and follow the instructions.

Windows: Do install the optional components of the C++ build tools package. The installation size may take up to 2 GB of disk space.

VS Code

Windows: Go to https://code.visualstudio.com and run the installer

Linux: Check your Linux distribution package manager (example below). If it's not there follow the instructions on https://code.visualstudio.com/docs/setup/linux

$ # Arch Linux
$ sudo pacman -S code

macOS: Go to https://code.visualstudio.com and click on "Download for Mac"

Rust Analyzer

All: Open VS Code and look for Rust Analyzer in the marketplace (bottom icon in the left panel). Then install it.

Windows: it's OK to ignore the message about git not being installed, if you get one

Rust Cross compilation support

All: Run this command in a terminal:

$ rustup +stable target add thumbv7em-none-eabi

ELF analysis tools

All: Run these commands in a terminal:

$ rustup +stable component add llvm-tools-preview

$ cargo install cargo-binutils

Python

Windows: Go to https://www.python.org/downloads/ and run the Python 3 installer

• in the installer check the "add Python 3.x to PATH" box
• also run the "Disable path length limit" action at the end, if you are on Windows 10 and the option is displayed to you

Linux: Install pip using the package manager; this will also install Python.

$ # Arch Linux
$ sudo pacman -S python-pip

macOS: Ensure that you have python 3 and pip installed. Refer to the following link for Instructions on how to install python 3 and pip

$ python --version
Python 3.7.7
$ pip --version
pip 20.0.2 from /usr/local/lib/python3.7/site-packages/pip (python 3.7)

nrfutil

All: Open a terminal and install nrfutil as follows. If you are familiar with python, it is advised to do this in a virtual environment.

$ pip install nrfutil
(..)

$ nrfutil version
nrfutil version 6.1.0

USB (Linux only)

Some of our tools depend on pkg-config and libudev.pc. Ensure you have the proper packages installed; on Debian based distributions you can use:

$ sudo apt-get install libudev-dev libusb-1.0-0-dev

To access the USB devices as a non-root user, follow these steps:

1. (Optional) Connect the dongle and check its permissions with these commands:

$ lsusb -d 1915:521f
Bus 001 Device 016: ID 1915:521f Nordic Semiconductor ASA USB Billboard
$ #   ^         ^^

$ # take note of the bus and device numbers that appear for you when run the next command
$ ls -l /dev/bus/usb/001/016
crw-rw-r-- 1 root root 189, 15 May 20 12:00 /dev/bus/usb/001/016

The root root part in crw-rw-r-- 1 root root indicates the device can only be accessed by the root user.

2. Create the following file with the displayed contents. You'll need root permissions to create the file.

$ cat /etc/udev/rules.d/50-oxidize-global.rules
# udev rules to allow access to USB devices as a non-root user

# nRF52840 Dongle in bootloader mode
ATTRS{idVendor}=="1915", ATTRS{idProduct}=="521f", TAG+="uaccess"

# nRF52840 Dongle applications
ATTRS{idVendor}=="2020", TAG+="uaccess"

# nRF52840 Development Kit
ATTRS{idVendor}=="1366", ATTRS{idProduct}=="1015", TAG+="uaccess"

3. Run the following command to make the new udev rules effective

$ sudo udevadm control --reload-rules

4. (Optional) Disconnect and reconnect the dongle. Then check its permissions again.

$ lsusb
Bus 001 Device 017: ID 1915:521f Nordic Semiconductor ASA 4-Port USB 2.0 Hub

$ ls -l /dev/bus/usb/001/017
crw-rw-r--+ 1 root root 189, 16 May 20 12:11 /dev/bus/usb/001/017

The + part in crw-rw-r--+ indicates the device can be accessed without root permissions.

JLink driver (Windows only)

On Windows you'll need to associate the nRF52840 Development Kit's USB device to the WinUSB driver.

To do that connect the nRF52840 DK to your PC using micro-USB port J2 (as done before) then download and run the Zadig tool.

In Zadig's graphical user interface,

1. Select the 'List all devices' option from the Options menu at the top.

2. From the device (top) drop down menu select "BULK interface (Interface 2)"

3. Once that device is selected, 1366 1015 should be displayed in the USB ID field. That's the Vendor ID - Product ID pair.

4. Select 'WinUSB' as the target driver (right side)

5. Click "Install WinUSB driver". The process may take a few minutes to complete.

nrf-recover

Some nRF52840 devices, specially older revisions, may have parts of their Flash memory locked. To unlock the memory use the nrf-recover tool.

This is only relevant to the nRF52840 Development Kit. First connect the nRF52840 DK to your PC using micro-USB J2 (as done before) then run the following commands:

$ cargo install nrf-recover

$ nrf-recover -y
Starting mass erase...
Mass erase completed, chip unlocked

Cargo subcommands

Install version v0.8.0 of the cargo-flash and cargo-embed subcommands, as well as the cargo-binutils subcommand, using the following commands:

$ cargo install cargo-flash --version 0.8.0 -f
(..)
Installed package `cargo-flash v0.8.0` (..)

$ cargo install cargo-embed --version 0.8.0 -f
(..)
Installed package `cargo-embed v0.8.0` (..)

$ cargo install cargo-binutils
(..)
Installed package `cargo-binutils v0.3.0` (..)