In our previous blog article about OpenWRT on Raspberry PI 2, we show how to build kernel image and file system for starting OpenWRT on Raspberry PI 2. On this article we will get overview about OpenWRT on Atmel SAMA5D3 platform with new Atmel WiFi module (WILC1000).
SAMA5D3-Xplained will be used as hardware platform for OpenWRT software.
SAMA5D3-Xplained board is supported by OpenWrt bleeding edge (r45580) Build root. Normally, when you are building OpenWRT images, at the end of compilation you will get kernel image and root file system (for SAMA5D3 this is UBI file system by default). But, linux image (built with OpenWRT buildroot) cannot be started normally with UBI file system, so we decided to use native Atmel AT91 kernel tree for building linux image. We just add some patches for supporting OpenWRT functionality to the Atmel AT91 kernel sources.Additionally, NAND Flash issue in Atmel AT91 kernel tree was fixed. This fix allows to start OpenWRT root file system (UBI) with Atmel AT91 kernel image.
For wireless connectivity, driver and firmware for Atmel WILC1000 module were added according ATWILC1000 Programming Guide. In such document very important point is setting up SDIO bus speed (MAX_SPEED value in «linux_wlan_sdio.c» file). We made test and WILC1000 is working stable with clock up to 48MHz.
Main OpenWRT window:
Realtime graphs windows in OpenWRT:
After OpenWRT was started on SAMA5D3-Xplained kit, we did WiFi benchmark test with iperf.
iPerf is a tool for active measurements of the maximum achievable bandwidth on IP network. The network link is delimited by two hosts running iPerf. One host must be set as client, the other one as server.
Result: The following result is output after 10 seconds.
Host machine output:
On next step, current (+5V input) was measured while SAMA5D3-Xpld board is booting (LAN cable connected to the ETH0/GETH):
As you can see on this diagram, the current was never cross 300mA border when Linux is booting and after booting - current becomes near 250mA.
When iperf performs testing with WiFi network:
Finally we got OpenWRT platform ready to make more complex device, where power consumption is very critical parameter.
Binaries for SAMA5D3-Xpld board with Atmel WILC1000 module also available below (need to use SAM-BA utility for programming).