This is the base Nerves System configuration for generic ARM platform emulated by QEMU.
| Feature | Description |
|---|---|
| CPU | Emulated single core ARM Cortex A9 |
| Memory | Per QEMU commandline |
| Storage | N/A |
| Linux kernel | 4.4.1 |
| IEx terminal | tty1 (the display) |
| GPIO, I2C, SPI | No |
| ADC | No |
| PWM | No |
| UART | No |
| Camera | No |
| Ethernet | Yes |
| WiFi | No |
| Bluetooth | No |
We've found working with QEMU to be slower than working with real hardware. This likely is due to us not configuring it appropriately, but keep this in mind if you use this system.
The most common way of using this Nerves System is create a project with mix nerves.new and to export MIX_TARGET=qemu_arm. See the Getting started
guide
for more information.
If you need custom modifications to this system for your device, clone this repository and update as described in Making custom systems
Unlike other Nerves systems, this one does not contain a minimal configuration since it is expected to be used exclusively for debugging on a fast computer. Currently, it contains the following additional packages:
- The
qt-webkit-kioskfullscreen browser
As such, it takes a long time to build if you need to make custom modifications to it. The goal is that rebuilds are uncommon. However, if you need to build this system it needs more than 4 GB of DRAM. You may also consider stripping down the configuration if qt-webkit-kiosk isn't needed.
The examples directory contains simple Nerves projects that demonstrate
uses of nerves_system_qemu_arm. The hello_nerves example follows closely to
the baseline Nerves getting started
example with the additions of
networking and ssh firmware update support. Here's how to use it:
cd examples/hello_nerves
export MIX_TARGET=qemu_arm
# Check the config/config.exs file to make sure that the ssh authorized
# key logic works for you. The nerves_firmware_ssh project has more info.
# Build it
mix deps.get
mix firmware
# Create the base image file. This is like a virtual SDCard for the emulator.
# It just needs to be done once and then you can use over-the-air updates
mix firmware.image
# Generate a shell script to invoke qemu (only needs to be done once)
mix nerves.gen.qemu_script
# Start qemu
./run-qemu.sh
# It should open a window and boot to an iex prompt. Since it's the first
# boot and the application data partition hasn't been formatted, you should
# see some log messages about it being corrupt and then it being formatted.
# At this point, feel free to make an edit to the Elixir code. For example,
# have it IO.puts something.
# When you're ready, build, and run a firmware update.
mix firmware
mix firmware.push
# See the nerves_firmware_ssh project for troubleshooting firmware updates
# and using OpenSSH's ssh client.The hello_nerves example also contains a trivial single page website to
demonstrate kiosk mode. To see it, start the example in QEMU and at the iex
prompt, run this:
:os.cmd('qt-webkit-kiosk -platform linuxfb -c /etc/qt-webkit-kiosk.ini').