- A20 dual core Cortex-A7 processor
- 1GB DDR3 memory
- AXP209 PMU IC
- MicroSD card
- UART console
- 4GB NAND Flash
- Status LEDs
- RESET, RECOVERY buttons
- 6 connectors x 40 pin 0.05" step
Official Images from OLIMEX
Note that only the microSD connector is suitable for booting the desired operating system, the SD-MMC connector is not suitable for booting since it is not a part of the boot sequence (refer to A20 datasheet).
A20 User Manual
A20 Users manual
Power supply and consumption
A20-OLinuXino-MICRO and A20-OLinuXino-MICRO-4GB basic dimensions in mils:
A20-OLinuXino is Open Source Hardware, CAD files are available at GitHub
The CAD product used to design OLinuXino is Eagle and you can download evaluation free version from their web.
How to correctly power off OLinuXino running from NAND Flash
In this Blog post we explain what are the problems. This is common problem for all computers running OS. Here you can read more about MLC NAND Flash and Linux file system.
How to generate boot-able SD-card Debian Linux image for A20-OLinuXino?
Follow our blog post with step by step instructions Note that Linux-Sunxi Kernel is a work-in-progress, this means you can try the current stage/sunxi-3.4 branch but if something is broken and doesn't work just revert to the git tags we give in the blog and they should work for sure
Sunxi u-boot loader The linux-sunxi git page contains a lot of sources for all Olimex Allwinner boards.
How to download new Android image to the NAND memory of my A20 board?
To repair the image on the NAND re-upload it following these steps:
- 2. Go to firmware tab of the program and point to a valid Android image (the latest official one may also be downloaded above).
- 3. Disconnect the power supply and USB cable from the A20 board.
- 4. Press and hold RECOVERY button, apply power supply (6-16)V, release RECOVERY button.
- 5. Connect USB cable to the mini USB connector.
- 6. You will be asked for drivers for the bootloader. Navigate to the folder where you extracted the PhoenixSuit and install the drivers from the respective executables (or manually point the installer to the drivers folder in the PhoenixSuit installation path).
- 7. PhoenixSuit will detect the board and would ask for the method of writing the image. Choose method of writing the image and confirm your wish to write the image.
- 8. Wait till upgrade succeeds
Note that it is not recommended to have your mini USB connected to an external USB hub. This might cause delays and might distort the signal levels. Always test with the USB connected straight to the USB ports of your computer.
How do I write the official Android image to a micro SD card for my A20 board?
There are two Android images available for an SD card. One for 7″ LCD and one for 10″ LCD A20-OLinuXino-MICRO#Android. Note that Android display configuration settings are edited in the script.bin file (it has to be converter to fex and edited according to the fex guide at linux sunxi's article; then converted back to script.bin and written in the image). To write the images on the SD card you will need PhoenixSuit and to follow these steps:
• Install and run PhoenixSuit
• Go to the firmware tab of the program and point to a valid Android image (note that the
images on Gdrive are compressed and you have to extract them to .img files to be able write
them with PhoenixSuit)
• Disconnect the power supply and USB cable from the A20 board. Put an SD card in micro SD
holder. We recommend 4GB class 10 card.
• Press and hold RECOVERY button, apply power supply (6-16)V, release RECOVERY button.
• Connect USB cable to the mini USB connector.
• You will be asked for drivers for the boot-loader. Navigate to the folder where you extracted the PhoenixSuit and install the drivers from the respective executables (or manually point the installer to the drivers folder in the PhoenixSuit installation path).
• PhoenixSuit will detect the board and would ask for the method of writing the image. Choose
method of writing the image and confirm your wish to write the image.
• Wait till upgrade succeeds
Note that it is not recommended to have your mini USB connected to an external USB hub. This
might cause delays and might distort the signal levels. Always test with the USB connected straight to the USB ports of your computer.
Important: When Android runs for very first time it takes several minutes to initialize all files and buffers please do not cut the power supply during this process! Also when fresh image is installed fast boot may be disabled, which means that when you apply power supply after few seconds Android will go in sleep mode and you have to press POWER button to start it, you can change to fast boot when you power off there is dialog box asking you if you want next boot to be fast boot, you have to check this box before you power off. Also note that you must do touch screen calibration when you run Android for very first time which might require a mouse.
How do I write the Linux image to a micro SD card to use with my A20 board?
To write a Linux image to an SD card under Windows we use Win32 Disk Imager):
- Download Win32 Disk Imager Win32 Disk Imager
- Insert card
- Start program
- Select file
- Click "write"
To write a Linux image to an SD card under Linux:
For instance you have an image with the file name of "debian_2g.img". It would be downloaded to the SD card connected to a Linux machine using one of the following commands:
- # dd bs=4M oflag=sync if=debian_2g.img of=/dev/sdX
- # cp debian_2g.img /dev/sdX
where X is the uSD card.
How to change HDMI, VGA and LCD resolutions?
The default SD card setup is made with settings for HDMI 720p/60Hz. If you want to change to some other LCD, VGA or HDMI resolution then you have to start change_display.sh script file in /root directory.
and press "Enter".
Then choose the resolution and the interface(LCD, HDMI or VGA). Note that the selection of a specific resolution is done by navigating with the arrow keys and pressing "space" button. Make sure the asterisk marks your selection properly.
The supported resolutions are:
- 1. 4.3" (480x272)
- 2. 7" (800x480)
- 3. 10" (1024x600)
- 4. 15.6" (1366x768)
Important: initially the boards are calibrated for a specific display. If you re-write the image (no matter whether the SD card or the NAND memory) you would need to use a mouse to calibrate the display initially. It might be impossible to calibrate it via touching the display.
- 0. 480i
- 1. 576i
- 2. 480p
- 3. 576p
- 4. 720p50
- 5. 720p60
- 6. 1080i50
- 7. 1080i60
- 8. 1080p24
- 9. 1080p50
- 10. 1080p60
For VGA: (note that the VGA signals are routed to custom 6 pin connector and you need from adapter to standard VGA connector)
- 0. 1680x1050
- 1. 1440x900
- 2. 1360x768
- 3. 1280x1024
- 4. 1024x768
- 5. 800x600
- 6. 640x480
- 7. 1920x1080
- 8. 1280x720
How to generate Arch Linux image?
Step by step instructions how to build Arch Linux image
How to detect and enable the Ethernet controller (if it is disabled by default)?
Note: in the previous Debian releases the Ethernet was auto-detected and initialized during boot BUT this was causing big delays in the start-up of the board if you didn't want to use Ethernet or if there wasn't Ethernet cable connected.
You can enable it by following these two steps:
1. To check under what name the LAN is associated write "ifconfig –a"
2. If, for example, it is under eth0 name, then write: "dhclient eth0"
This should enable the Ethernet and then SSH would also be available.
How to install Android on SD-card?
Blog post about it
How to access UART, I2C, GPIOs under Android?
Use our Open Source OLinuXino A20-TOOLS
How to control PWM under Linux?
There is an article here: how to add pwm
How to build the Android 4.2.2 image for A20-OLinuXino-MICRO?
First you need to Download the A20 SDK2.0 Linux Kernel 3.4
Second you need to configure your environment read the instructions here
Then Build the kernel, kernel modules and u-boot
When done, continue with Bulding the android image:
tar zxfv olinuxino-a20.tgz
lunch #select olinuxino-a20_eng
Dave from Axon instruments wrote more detailed blog post about how he generates the Android image]
How to build Debian Linux 3.4 image for A20-OLinuXino-MICRO?