OpenWrt for Raspberry Pi is compiled with the ARM soft-float kernel ABI. This means that non-integer math is done in software instead of in hardware. Soft float (armel) is slower than hard float (armhf).
The Raspberry Pi is supported in the brcm2708 target. Releases with support for this target are:
|2014-10-02||14.07 Barrier Breaker||http://downloads.openwrt.org/barrier_breaker/14.07/brcm2708/generic/|
|2013-04-25||12.09 Attitude Adjustment||http://downloads.openwrt.org/attitude_adjustment/12.09/brcm2708/generic/|
|2012-07-24||Trunk r32825 - Add support for Raspberry Pi / brcm2708 / 2835||https://dev.openwrt.org/changeset/32825|
If you are not sure which file to get, download openwrt-brcm2708-sdcard-vfat-ext4.img
|Broadcom BCM2835||700 MHz ARM11 ARM1176JZF-S||via GPIO||via GPIO||MicroUSB A|
|RPi Model||RAM||Network||USB||Memory Card||Video||Audio||Power Requirements||GPIO Pins|
|A||256 MB||None||1 USB port||SD Card||HDMI and Composite RCA||3.5mm Stereo||5V 300mA (see below)||8|
|B||256 or 512 MB||10M/100M Ethernet RJ45||2 USB ports||SD Card||HDMI and Composite RCA||3.5mm Stereo||5V 700mA (see below)||8|
|B+||512 MB||10M/100M Ethernet RJ45||4 USB ports||MicroSD||HDMI and shared TRSS 3.5mm||Shared TRSS 3.5mm||5V 600mA (see below)||17|
The power figures quoted are the bare minimum to run the SoC with no peripherals. Most people find at least a solid 1A is required, especially if adding USB peripherals like keyboard, mouse, or wifi.
A popular power supply is the Apple 12W iPad charger, supplying 5V 2.4A. Similar high-powered mobile phone and tablet chargers should suffice. Using cheap power supplies off eBay is not recommended, as they provide a very uneven and noisy current which can lead to unreliable operation.
It is possible to back-power some Raspberry Pi models from the USB ports, however this is not recommended, as the power in from the USB ports is not protected against surges whereas the main power supply is protected.
It is also possible to supply the required power via the GPIO pins.
Serial is available via GPIO.
|Pin 6||Pin 8||Pin 10|
Connect via RS232 at 3.3 Volts (not older 12V). 115200 bps 8N1.
On a Linux desktop, insert your SD card and run:
to see the latest kernel messages.
The most recent message should give you the SD card's device name, such as sdb or sdf or similar.
Download the relevant openwrt-brcm2708-sdcard-vfat-ext4.img image.
As the root user, use dd to copy the image file to the device you identified previously, for example:
dd if=/home/username/Downloads/openwrt-brcm2708-sdcard-vfat-ext4.img of=/dev/sdX bs=2M conv=fsync
Replace the sdX with your device name, such as sdb or sdf.
On a Windows desktop, use Win32DiskImager to copy the img file to your SD card's drive letter.
There are many more complex guides around the internet to flashing images to SD cards,
- Raspberry_Pi - Wikipedia
- Raspberry Pi hub on eLinux Wiki is an excellent place to get started for all things Raspberry Pi
- Raspbian is a Debian port containing only the few modifications to the Debian source required to compile for the Pi's ARMv6 instruction set
- https://sites.google.com/site/variousopenwrt/rpi-patch/ - no longer required
- Gemscool - Forum Raspberry_Pi
- http://thread.gmane.org/gmane.comp.embedded.openwrt.devel/14815 - openwrt-devel post adding RPi support
- recent state of Raspberry PI support - OpenWrt Forum thread
- Apple Ipad - required raspberry apple
- Benjamin Henrion: Raspberry Pi with Openwrt - shows Pi running, plus serial and JTag
toh/raspberry_pi.txt · Last modified: 2014/11/19 20:13 by xiloynaha