Raspberry Pi Model Zero
This is the base Nerves System configuration for the Raspberry Pi Zero and Raspberry Pi Zero W.
If you are not interested in Gadget Mode it might be worth checking out nerves_system_rpi. That image configures the USB port in host mode by default and is probably more appropriate for your setup.
[Image credit](#fritzing)
Feature | Description |
---|---|
CPU | 1 GHz ARM1176JZF-S |
Memory | 512 MB |
Storage | MicroSD |
Linux kernel | 4.4 w/ Raspberry Pi patches |
IEx terminal | OTG USB serial port (ttyGS0 ). Can be changed to HDMI or UART. |
GPIO, I2C, SPI | Yes - Elixir ALE |
ADC | No |
PWM | Yes, but no Elixir support |
UART | 1 available - ttyAMA0 |
Camera | Yes - via rpi-userland |
Ethernet | Yes - via OTG USB port |
WiFi | Supported on the Pi Zero W |
Bluetooth | Not supported yet |
Console and kernel message configuration
The goal of this image is to use the OTG port for console access. If you’re
debugging the boot process, you’ll want to use the Raspberry Pi’s UART pins on
the GPIO connector or the HDMI output. This is enabled by updating the
cmdline.txt
file. This may be overridden with a custom fwup.conf
file if
you don’t want to rebuild this system. Add the following to your cmdline.txt
:
console=ttyAMA0,115200 console=tty1 ...
If you’d like the IEx prompt to come out the UART pins (ttyAMA0
) or HDMI
(tty1
), then modify rootfs_overlay/etc/erlinit.config
as well.
Supported OTG USB modes
The base image activates the dwc2
overlay, which allows the Pi Zero to appear as a
device (aka gadget mode). When plugged into a host computer via the OTG port, the Pi
Zero will appear as a composite Ethernet and serial device. The virtual serial
port provides access to the IEx prompt and the Ethernet device can be used for
firmware updates, Erlang distribution, and anything else running over IP.
Supported WiFi devices
The base image includes drivers for the onboard Raspberry Pi Zero W wifi module
(brcmfmac
driver). Due to the USB port being placed in gadget mode, this
system does not support USB WiFi adapters.
Linux kernel and RPi firmware/userland
There’s a subtle coupling between the nerves_system_br
version and the Linux
kernel version used here. nerves_system_br
provides the versions of
rpi-userland
and rpi-firmware
that get installed. I prefer to match them to
the Linux kernel to avoid any issues. Unfortunately, none of these are tagged
by the Raspberry Pi Foundation so I either attempt to match what’s in Raspbian
or take versions of the repositories that have similar commit times.
Installation
If you’re new to Nerves, check out the nerves_init_gadget project for creating a starter project for the Raspberry Pi Zero or Zero W. It will get you started with the basics like bringing up the virtual Ethernet interface, initializing the application partition, and enabling ssh-based firmware updates.
Image credit: This image is from the Fritzing parts library.