A20-OLinuXino-MICRO

A20-OLinuXino-MICRO features:

• A20 Cortex-A7 dual-core ARM Cortex-A7 CPU and dual-core Mali 400 GPU
• 1GB DDR3 RAM memory
• Optional 4GB NAND FLASH memory
• SATA connector with 5V SATA power jack
• HDMI FullHD 1080p
• 2x USB Low-Full-High-Speed hosts with power control and current limiter
• USB-OTG with power control and current limiter
• VGA output on 6-pin 1.25mm (0.05") step connector
• 100MBit native Ethernet
• LiPo Battery connector with battery-charging capabilities
• Audio headphones output
• Microphone input on connector
• 2x UEXT connectors
• LCD connector compatible with with 4.3", 7.0", 10.1" LCD modules from Olimex
• 160 GPIOs on three GPIO connectors
• MicroSD card connector
• SD/MMC card connector
• DEBUG-UART connector for console debug with USB-SERIAL-CABLE-F
• status LED
• Battery charge status LED
• Power LED
• 2KB EEPROM for MAC address storage and more
• 10 BUTTONS with ANDROID functionality + RESET button
• 4 mount holes
• 6-16V input power supply, noise immune design
• PCB dimensions: 142 x 82 mm

Official Images Recommended by Olimex

Below you would find links to the official Debian and Android images. The images in this chapter were compiled by Olimex. They are recommended for beginners and first time users since they include full hardware support. If you are experienced Linux professional you might find bare-bone images and much more in the next chapter "Notable unofficial images".

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).

The downloaded file xxxx.7z is an archive of xxx.img file. In order to write the image on SD card you have to unzip the xxx.7z file.

• For Windows: use 7zip and then use Win32DiskImager.exe (http://sourceforge.net/projects/win32diskimager/) to write the image

• For Linux: use p7zip package. If you don't have 7zip installed first install it
  
  

   #apt-get install p7zip

Copy a20_debian_second_release.7z file in your directory and unzip the archive with

   #7za e a20_debian_second_release.7z

where a20_debian_second_release.7z The output should be a new 4GB file with extension img Put 4GB SD card in your card reader and type

   # ls /dev/sd

Then press two times <TAB> you will see a list of your sd devices like sda sdb sdc note that some of these devices may be your hard disk so make sure you know which one is your sd card before you proceed as you can damage your HDD if you choose the wrong sd-device. You can do this by unplugging your sd card reader and identify which "sd" devices remove from the list. Once you know which device is your sdcard like sda use this text instead of the sdX name in the references below:

   #dd if=a20_debian_second_release.img of=/dev/sdX

Linux

The official Debian images are suitable only for microSD card. Information on booting Debian from the NAND might be found at the forum. Download methods and locations might be found below!

Newest official release (recommended):

Torrent of Debian release 10: A20-OLinuXino-MICRO Debian with kernel 3.4.90+ release 10

Build instructions and required files for the latest Debian images: instructions and files at the GitHub page

Older official releases (not recommended):

Torrent of Debian release 8: A20-OLinuXino-MICRO Debian with kernel 3.4.90+ release 8

Direct download of Debian release 7: A20-OLinuXino-MICRO Debian with kernel 3.4.67+ release 7

The newest release has the following features:

• Default Login: root/olimex
• Linux Kernel 3.4.90+
• LXDE desktop environment
• Mplayer CLI
• smplayer
• Midori browser
• GCC 4.6
• GPIO support
• i2c-tools
• dpkg
• git
• perl
• xorg
• Python 2.7
• OpenCV
• Scratch
• vlc
• minicom
• HDMI
• Micro SD card
• SD/MMC card
• OTG USB
• HIGH SPEED HOST1 USB
• HIGH SPEED HOST2 USB
• ETHERNET 100MBIT
• SATA
• Audio IN
• Audio OUT
• Kernel support for USB-ETHERNET-AX88772B
• Kernel suppot for MOD-WIFI-RTL8188
• Support for Olimex-made displays and touchscreens: A13-LCD43TS 4.3″ LCD with backlight and touchscreen 480×272 pixels; A13-LCD7TS 7″ LCD with backlight and touchscreen 800×480 pixels; A10-LCD10TS 10.1″ LCD with backlight and touchscreen 1024×600 pixels;

Tested board peripherals with this image:

• GPIO - located at /sys/class/gpio
• LCD - supported LCD displays and touchscreens are the Olimex-made ones A13-LCD4.3TS, A13-LCD7TS, A13-LCD10TS
• Touch screen - you need calibrate LCD before using touch screen. Type: ts_calibrate and then test it with ts_test
• SATA - works including power on/off control
• HDMI - the default HDMI resolution is 720p60(1280x720-60 Hz)
• ASIX 8877 USB-LAN - USB-ETHERNET-AX88772B
• WEB camera A4TECH
• TL-WN721(TP-LINK USB wireless)
• RTL8188CU - MOD-WIFI-RTL8188 - instructions on configuration might be found here How_to_configure_MOD-RTL8188_on_official_OLinuXino_Debian_releases
• USB_OTG - works as OTG device and Low/Full/High USB host
• USB_HOST_up - works as Low/Full/High USB host
• USB_HOST_down - works as Low/Full/High USB host
• mico_SD_card - allow Linux boot
• secondary SD-MMC card - with card present detector
• ETHERNET - 100Mb
• Headphone OUT - audio output
• MIC IN - microphone input
• I2C2(100KHz) - /dev/i2c-2
• I2C1(100KHz) - /dev/i2c-1
• UART6 - /dev/ttyS1
• UART7 - /dev/ttyS2

Note: the A20-Debian-SD card which we have in our web store contains the same image on 4GB Class10 fast micro SDcard, if you want to use this image please use card of Class10 speed or the performance of Linux will be very slow.

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.

Android

Torrents of official Android releases are below. Please read description of the image carefully.

Torrent of Android release 3 for NAND memory with HDMI and 7 inch LCD (800x480) support: A20-OLinuXino Android for NAND with HDMI and 800x480 video support

Torrent of Android release 3 for NAND memory with HDMI and 10 inch LCD (1024x600) support: A20-OLinuXino Android for NAND with HDMI and 1024x600 video support

Torrent of Android release 1 for microSD card with HDMI and 7 inch LCD (800x480) support: A20-OLinuXino Android for microSD card with HDMI and 800x480 video support

Torrent of Android release 1 for microSD card with HDMI and 10 inch LCD (1024x600) support: A20-OLinuXino Android for microSD card with HDMI and 1024x600 video support

Direct download of Android 4.2.2 NAND image made with A20-SDK2.0 for A13-LCD7"TS and A13-LCD10"TS

Direct download of Android 4.2.2 SD-card image made with A20-SDK2.0 for A13-LCD7"TS and A13-LCD10"TS

The Android image has the following features:

• Android 4.2.2
• NAND image i.e. will work only on A20-OLinuXino-MICRO-4GB
• Supports 7" LCD 800x480 pixels and 10" LCD 1024x600 pixels
• HDMI support (720p default)
• both LCD and HDMI work together
• Touchscreen supported
• GPIO support
• Native Ethernet 100Mbit
• USB-Ethernet ASIX 88772
• USB-WIFI RTL8188
• USB-OTG support USB device and USB host with Low/Full/High speed
• USB-HOST-top Low/Full/High speed
• USB-HOST-bottom Low/Full/High speed
• micro SD card
• Audio OUT
• Audio In
• I2C1
• I2C2
• UART6
• UART7
• Buttons

What is left unsupported in Android:

• SATA
• SD-MMC card on bottom

Notable unofficial images

Below you would find locations to images released by the community. These are not officially supported by Olimex, however, some of these releases are pretty good and worth a try:

A number of very good and optimized A20-OLinuXino-LIME Debian images by Igor Pečovnik. There are also instructions for NAND installation of Debian: link to his web-sitee]

Documents

A20-OLinuXino Board User Manual

A20-OLinuXino User Manual

A20 Brief

A20-Brief description

A20 Datasheet

A20 datasheet

A20 User Manual

A20 Users manual

Hardware

Power supply and consumption

A20-OLinuXino can be powered from three sources:

• +6-16VDC voltage applied PWR jack
• +3.7V from LiPo re-chargable battery connected to LiPo board connector
• +5V applied to USB-OTG connector

Power consumption is as follows:

• LiPo 3.7V power battery: 0.17-0.25A depend on processor load
• +6VDC input power: 0.18-0.33A depend on processor load
• +16VDC input power: 0.11-0.17A depend on processor load

Comparison table of power consumption might be found at the following link.

LiPo battery allow backup power supply when main power is interrupted. A20-OLinuXino have power managment IC which charge the battery when main power is present, when power is interrupted the LiPo battery automatically provide backup power supply. Step-up converter prvide 5V for the USB peripherials too. For LiPo batteries we recommend these:

• 1400mAh
• 3000mAh
• 4400mAh
• 6600mAh

Board dimensions

A20-OLinuXino-MICRO and A20-OLinuXino-MICRO-4GB basic dimensions in mils: image in PNG format

CAD files

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.

Board Layout

Be careful with TV monitors without grounding

Here you can read how easy you can damage your OLinuXino if you connect it to TV without grounding.

Software

Linux Commands

Linux-Commands Brief Linux Command reference

Python

pyA20 is Python library for access to A20-OLinuXino-MICRO GPIOs, I2C, SPI

Use:

   #!/usr/bin/env python
   
   import A20_GPIO as GPIO
   
   #init module
   GPIO.init()
   
   #configure module
   GPIO.setcfg(GPIO.PIN#, GPIO.OUTPUT)
   GPIO.setcfg(GPIO.PIN#, GPIO.INPUT)
   
   #read the current GPIO configuration
   config = GPIO.getcfg(GPIO.PIN#)
   
   #set GPIO high
   GPIO.output(GPIO.PIN#, GPIO.HIGH)
   
   #set GPIO low
   GPIO.output(GPIO.PIN#, GPIO.LOW)
   
   #read input
   state = GPIO.input(GPIO.PIN#)
   
   #cleanup
   GPIO.cleanup()

GPIO under Linux

A very good GPIO guide by Dr. Guido Pelz might be found here: http://www.py6zgp.com/download/A20-GPIO.pdf

You can read data from a given GPIO port. The logical ranges are usually as follows: 0V-1V for LOW (or 0) and 2.4V-3.3V for HIGH (or 1). All voltages are measured against ground (GND).

If the input signal is to high, you will at least destroy the port!

In order to use A20 GPIO's first you have to export them. You can export a single GPIO:

   root@A20:~# echo gpioXX > /sys/class/gpio/export

To export a range of GPIOs (from 1-230 in the example below) use:

   root@A20:~#  for i in `seq 1 1 230`; do echo $i > /sys/class/gpio/export; done

list of all available GPIO

   root@A20:~# ls /sys/class/gpio/
   export       gpio21_pc3/  gpio33_pb8/  gpio45_ph27/ gpio57_ph17/ gpio69_pg5/
   gpio10_pe9/  gpio22_pc7/  gpio34_pb10/ gpio46_ph0/  gpio58_ph18/ gpio6_pe5/
   gpio11_pe10/ gpio23_pc16/ gpio35_pb11/ gpio47_ph2/  gpio59_ph19/ gpio70_pg6/
   gpio12_pe11/ gpio24_pc17/ gpio36_pb12/ gpio48_ph7/  gpio5_pe4/   gpio71_pg7/
   gpio13_pi14/ gpio25_pc18/ gpio37_pb13/ gpio49_ph9/  gpio60_ph20/ gpio72_pg8/
   gpio14_pi15/ gpio26_pc23/ gpio38_pb14/ gpio4_pe3/   gpio61_ph21/ gpio73_pg9/
   gpio15_pi0/  gpio27_pc24/ gpio39_pb15/ gpio50_ph10/ gpio62_ph22/ gpio74_pg10/
   gpio16_pi1/  gpio28_pb3/  gpio3_pe2/   gpio51_ph11/ gpio63_ph23/ gpio75_pg11/
   gpio17_pi2/  gpio29_pb4/  gpio40_pb16/ gpio52_ph12/ gpio64_pg0/  gpio7_pe6/
   gpio18_pi3/  gpio2_pe1/   gpio41_pb17/ gpio53_ph13/ gpio65_pg1/  gpio8_pe7/
   gpio19_pi10/ gpio30_pb5/  gpio42_ph24/ gpio54_ph14/ gpio66_pg2/  gpio9_pe8/
   gpio1_pe0/   gpio31_pb6/  gpio43_ph25/ gpio55_ph15/ gpio67_pg3/  gpiochip1/
   gpio20_pi11/ gpio32_pb7/  gpio44_ph26/ gpio56_ph16/ gpio68_pg4/  unexport

Example on how to write to a GPIO. For instance - toggle onboard LED. The LED is connected to PH2.

1. Export gpio47_ph2

   root@A20:~# echo gpio47 > /sys/class/gpio/export

2. Set PH2 as output

   root@A20:/sys/class/gpio/gpio47_ph2# echo out > direction

3. Set high position (1) of PH2 - LED is ON

   root@A20:/sys/class/gpio/gpio47_ph2# echo 1 > value

4. Set low position (0) of PH2 - LED is OFF

   root@A20:/sys/class/gpio/gpio47_ph2# echo 0 > value

Example on how to read GPIO (with GPIO #49):

1. Export GPIO 49

   echo 49 > /sys/class/gpio/export

2. Set input

   echo "in" > /sys/class/gpio/gpio49_ph9/direction

3. Read value GPIO 49

   cat /sys/class/gpio/gpio49_ph9/value 

4. Unexport GPIO 49 when finished

   echo 49 > /sys/class/gpio/unexport

Add Voice to your OLinuXino project

Installation of Festival on OLinuXino

How To?

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?

Build instructions and required files for the latest Debian images: instructions and files at the GitHub page

Official Olimex wordpress article on how to extend the previous build of Debian Linux 3.4 with hardware acceleration support, keep a look at the wordpress for more interesting articles

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:

• 1. Install and run PhoenixSuit (can be found here: download from google drive).

• 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

or

• # 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.

Type:

   ./change_display*

or

   ./change_display_A20_OLinuXino.sh

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:

For LCD:

• 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.

For HDMI:

• 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

   cd lichee
   ./build.sh -psun7i_android

When done, continue with Bulding the android image:

   cd ../android4.2
   cd device/softwinner/
   tar zxfv olinuxino-a20.tgz
   cd ../../
   source build/envsetup.sh
   lunch #select olinuxino-a20_eng
   extract-bsp
   make -j4

Dave from Axon instruments wrote more detailed blog post about how he generates the Android image

How to edit board configurations and definitions in the official Debian Linux?

It is described in this wiki article: How_to_edit_board_configurations_and_definitions_in_the_official_Debian_Linux.

How to properly calibrate a display under Debian

If the problem is under Debian Linux make sure you are properly logged in the LXDE visual interface! Else applying calibration would not happen for the current user - if you are calibrating from the X graphical interface make sure that you are logged as user “olimex” (if calibrating without the X, the user is “root”).

   #su olimex

enter the olimex password:olimex

   #sudo ts_calibrate

calibrate the touch screen and reboot the board

   #sudo reboot

It would be a good idea to test with Android or another Debian image also, it has a built-in calibration application by default.

How to add STK1160 video capture driver support in Kernel 3.4

STK1160 driver backport by Dimitar Tomov

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