OLIMEX© 2018
A20-OLinuXino-MICRO user's manual
USB_HOST two-level connector
Pin # Signal name Processor pin
Pin #
Signal name
Processor pin
1.1
5V
Connected to SY628
2.1
5V
Connected to SY628
1.2
UDM1
P20
2.2
UDM2
R20
1.3
UDP1
P21
2.3
UDP2
R21
1.4
GND
-
2.4
GND
-
The GND is common for both levels of the USB_HOST.
6.7 Ethernet
In different hardware revisions of the board we have used a number of different megabit Ethernet
controllers. This is why it is important to test with the latest official image first.
In hardware revision J of the board we switched to Microchip's LAN8710AI-EZK(QFN-32). Note
that the industrial version of the board uses industrial version of the chip. Make sure to refer to the
hardware schematic for exact information about the chip used.
If you have problems with the software support for the Ethernet in Linux, consider checking our
latest build instructions and patches. At the time of writing, a patch to get the Ethernet working can
be found here:
https://github.com/OLIMEX/OLINUXINO/blob/master/SOFTWARE/A20/A20-
build-3.4.103-release-5/a20-phy_1000_100-dram.patch
If you use Linux then the Ethernet connector might be used for SSH connection to the board. If you
lack any other option for debugging it might be hard to guess the correct IP of the board since it has
DHCP enabled by default (especially if you are in a large network). It is good idea to check the
default settings by exploring the Linux image settings. Those are usually stored in:
/etc/network/interfaces
For DHCP you need to enable auto detection and dhcp as shown below:
auto eth0
iface eth0 inet dhcp
For setting a static address please follow the pattern below:
auto eth0
iface eth0 inet static
address 192.168.1.5
netmask 255.255.255.0
gateway 192.168.1.254
The EEPROM memory may be used to store the MAC address.
Important: In some Debian images it is possible that the Ethernet doesn't get auto-detected during
boot-up. This is done on purpose because if there is auto-detection enabled and you don't want to
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