# Raspberry Pi Model A+, B, and B+
[](https://circleci.com/gh/nerves-project/nerves_system_rpi)
[](https://hex.pm/packages/nerves_system_rpi)
This is the base Nerves System configuration for the Raspberry Pi A+, B,
and B+. It will also work with the Raspberry Pi Zero, but usually
[nerves_system_rpi0](https://github.com/nerves-project/nerves_system_rpi0) is
preferable since it configures the USB port so that it can be plugged into
a computer. This is very convenient for powering and debugging the Pi Zero.
If you want to use the Raspberry Pi Zero's USB port in "host" mode (e.g.,
to attach a USB Flash drive or other peripheral), then this repository
works and may be more appropriate.
This is not the configuration for the Raspberry Pi 2 or 3.
<br><sup>[Image credit](#fritzing)</sup>
| Feature | Description |
| -------------------- | ------------------------------- |
| CPU | 700 MHz ARM1176JZF-S for A+, B, and B+, 1 GHz ARM1176JZF-S for the Zero |
| Memory | 256 MB for rev 1 boards, 512 MB for rev 2 and the Zero |
| Storage | MicroSD |
| Linux kernel | 4.4.50 w/ Raspberry Pi patches |
| IEx terminal | HDMI and USB keyboard (can be changed to 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 |
| WiFi | Requires USB WiFi dongle |
| Bluetooth | Not supported |
## Supported USB WiFi devices
The base image includes drivers and firmware for Ralink RT53xx
(`rt2800usb` driver) and RealTek RTL8712U (`r8712u` driver) devices.
We are still working out which subset of all possible WiFi dongles to
support in our images. At some point, we may have the option to support
all dongles and selectively install modules at packaging time, but until
then, these drivers and their associated firmware blobs add significantly
to Nerves release images.
If you are unsure what driver your WiFi dongle requires, run Raspbian and configure WiFi
for your device. At a shell prompt, run `lsmod` to see which drivers are loaded.
Running `dmesg` may also give a clue. When using `dmesg`, reinsert the USB
dongle to generate new log messages if you don't see them.
## 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](https://github.com/fhunleth/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](#fritzing): This image is from the [Fritzing](http://fritzing.org/home/) parts library.
