OLIMEX A20-OLinuXino-MICRO-e4Gs16M User manual

A20-OLinuXino-MICRO
Open-source single-board
Android/Linux mini-computer
U ER’ MANUAL
Document revision S, March 2018
Designed by OLIMEX Ltd, 201
All boards produced by Olimex LTD are ROHS compliant

OLIMEX© 018 A 0-OLinuXino-MICRO user's manual
DISCLAIMER
© 018 Olimex Ltd. Olimex®, logo and combinations thereof, are registered trademarks of Olimex Ltd. Other product
names may be trademarks of others and the rights belong to their respective owners.
The information in this document is provided in connection with Olimex products. No license, express or implied
or otherwise, to any intellectual property right is granted by this document or in connection with the sale of
Olimex products.
This work is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License. To view a copy of
this license, visit http://www.creativecommons.org/licenses/by-sa/3.0/.
This hardware design by Olimex LTD is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported
License.
The software is released under GPL.
It is possible that the pictures in this manual differ from the latest revision of the board.
The product described in this document is subject to continuous development and improvements. All particulars of the
product and its use contained in this document are given by OLIMEX in good faith. However all warranties implied or
expressed including but not limited to implied warranties of merchantability or fitness for purpose are excluded. This
document is intended only to assist the reader in the use of the product. OLIMEX Ltd. shall not be liable for any loss or
damage arising from the use of any information in this document or any error or omission in such information or any
incorrect use of the product.
This evaluation board/kit is intended for use for engineering development, demonstration, or evaluation purposes only
and is not considered by OLIMEX to be a finished end-product fit for general consumer use. Persons handling the
product must have electronics training and observe good engineering practice standards. As such, the goods being
provided are not intended to be complete in terms of required design-, marketing-, and/or manufacturing-related
protective considerations, including product safety and environmental measures typically found in end products that
incorporate such semiconductor components or circuit boards.
Olimex currently deals with a variety of customers for products, and therefore our arrangement with the user is not
exclusive. Olimex assumes no liability for applications assistance, customer product design, software performance, or
infringement of patents or services described herein.
THERE IS NO WARRANTY FOR THE DESIGN MATERIALS AND THE COMPONENTS
USED TO CREATE A20-OLINUXINO-MICRO. THEY ARE CONSIDERED SUITABLE
ONLY FOR A20-OLINUXINO-MICRO.
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Table of Contents
DI CLAIMER ............................................................................................................. 2
CHAPTER 1: OVERVIEW ........................................................................................ 5
1. Introduction to the chapter .......................................................................................................
1.1 Features .....................................................................................................................................
1.2 Target market and purpose of the board ............................................................................... 6
1.3 Board variants .......................................................................................................................... 6
1.4 Board version used in the manual .......................................................................................... 7
1. Organization ............................................................................................................................. 7
CHAPTER 2: ETTING UP THE OLINUXINO BOARD ..................................... 8
2. Introduction to the chapter ....................................................................................................... 8
2.1 Electrostatic and electrical polarity warning ........................................................................ 8
2.2 Requirements ........................................................................................................................... 8
2.3 Powering the board ................................................................................................................ 10
2.4 Prebuilt software .................................................................................................................... 11
2. Button functions ..................................................................................................................... 11
2.6 Interacting with the board .................................................................................................... 12
2.6.1 HDMI monitor .............................................................................................................................................. 12
2.6.2 VGA monitor ................................................................................................................................................. 13
2.6.3 H via mini U B cable in Debian ............................................................................................................. 13
2.6.4 H via Ethernet .......................................................................................................................................... 13
2.6.5 LCD display .................................................................................................................................................. 13
2.7 Changing the default image resolution ................................................................................ 14
2.8 Connecting a display and calibrating touchscreen ............................................................. 16
2.8.1 Android toucshcreen calibration ................................................................................................................. 16
2.8.2 Debian touchscreen calibration ................................................................................................................... 16
2.9 GPIO under Debian ............................................................................................................... 17
2.10 I2C and SPI under Debian .................................................................................................. 18
2.11 Software support .................................................................................................................. 18
CHAPTER 3: A20-OLINUXINO-MICRO BOARD DE CRIPTION ................. 19
3. Introduction to the chapter ..................................................................................................... 19
3.1 Layout (top view) ................................................................................................................... 19
3.2 Layout (bottom view) ............................................................................................................. 20
CHAPTER 4: THE ALLWINNER A20 EMBEDDED PROCE OR ................. 21
4. Introduction to the chapter ..................................................................................................... 21
4.1 The processor ......................................................................................................................... 21
4.2 Block diagram ........................................................................................................................ 22
CHAPTER 5: CONTROL CIRCUITY ................................................................... 23
. Introduction to the chapter ..................................................................................................... 23
.1 Reset ........................................................................................................................................ 23
.2 Clocks ...................................................................................................................................... 23
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.3 Power supply circuit .............................................................................................................. 23
CHAPTER 6: CONNECTOR AND PINOUT ...................................................... 24
6. Introduction to the chapter ..................................................................................................... 24
6.1 Communication with the A20 ............................................................................................... 24
6.1.1 U B-OTG communication (NAND firmware repair/update) .................................................................. 24
6.1.2 UART0, UEXT1, UEXT2 interface ............................................................................................................ 26
6.2 SD card connectors ................................................................................................................ 27
6.2.1 D/MMC1 slot .............................................................................................................................................. 28
6.2.2 D/MMC slot ................................................................................................................................................ 29
6.3 PWR jack ................................................................................................................................ 30
6.4 MIC_IN & HEADPHONES connectors .............................................................................. 30
6. USB_OTG connector ............................................................................................................. 31
6.6 USB_HOST connector ........................................................................................................... 33
6.7 Ethernet .................................................................................................................................. 34
6.8 HDMI connector .................................................................................................................... 36
6.9 VGA connector ....................................................................................................................... 37
6.10 SATA connector and power ................................................................................................. 38
6.11 GPIO ports ............................................................................................................................ 39
6.11.1 GPIO-1 (General Purpose Input/Output) 40pin connector** ................................................................ 39
6.11.2 GPIO-2 (General Purpose Input/Output) 40pin connector .................................................................... 40
6.11.3 GPIO-3 (General Purpose Input/Output) 40pin connector .................................................................... 41
6.12 LCD_CON 40pin connector ................................................................................................ 43
6.13 Jumper description .............................................................................................................. 44
6.14 Additional hardware components ...................................................................................... 4
CHAPTER 7: CHEMATIC .................................................................................. 46
7. Introduction to the chapter ..................................................................................................... 46
7.1 Eagle schematic ...................................................................................................................... 46
7.2 Physical dimensions ............................................................................................................... 47
CHAPTER 8: REVI ION HI TORY AND UPPORT ........................................ 48
8. Introduction to the chapter ..................................................................................................... 48
8.1 Document revision ................................................................................................................. 48
8.2 Board revision ........................................................................................................................ 0
8.3 Useful web links and purchase codes ................................................................................... 2
8.4 Frequently asked questions (FAQ) ....................................................................................... 3
8. Product support ..................................................................................................................... 6
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OLIMEX© 018 A 0-OLinuXino-MICRO user's manual
CHAPTER 1: OVERVIEW
1. Introduction to the chapter
Thank you for choosing this A 0 single board computer from Olimex! This document provides a
user’s guide for the Olimex A 0-OLinuXino-MICRO board. As an overview, this chapter gives the
scope of this document and lists the board’s features. The document’s organization is then detailed.
The A 0-OLinuXino-MICRO development board allows evaluation of the A 0 processor,
manufactured by Allwinner Technology from China. The board is suitable for research and
development, but it can also be embedded in own products.
OLinuXino is an open-source, open-hardware project and all documentation that we used to
manufacture the board is available to the customer.
1.1 Features
The board has the following set of features (please note the difference between the two versions of
the board):
•A 0 Cortex-A7 dual-core ARM Cortex-A7 CPU and dual-core Mali 400 GPU
•1GB DDR3 RAM memory
•4GB or 8GB NAND FLASH memory (available only on certain variants of the board)
•4GB eMMC memory (available only on certain variants of the board)
•Industrial temperature range versions available (boards with “-IND” suffix)
•SATA connector with 5V SATA power jack
•Capable of FullHD (1080p) video playback
•Native HDMI output with connector; VGA output on 6-pin 1. 5mm (0.05'') step connector
• x USB High-speed host with power control and current limiter
•USB-OTG with power control and current limiter
•100MBit native Ethernet
•Battery connector with battery-charging capabilities
•Audio headphones output on connector
•Microphone input on connector
• x UEXT connectors
•LCD connector compatible with with 4.3'', 7.0'', 10.1" LCD displays 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
•Battery charge status LED and GPIO LED
•KB EEPROM for MAC address storage and more
•10 BUTTONS with ANDROID functionality + RESET button
•4 mount holes
•Power jack for external power supply (7- 4)V DC1
•PCB dimensions: (5600×3 50) mils ~ (14 . 4×8 .55) mm
1 For boards revision J or newer; the voltage applied to the power jack should be (6-16)V for older board revisions
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1.2 Target market and purpose of the board
The boards from the OLinuXino family are easy to setup and powerful. It is possible to use them in
almost any application as a host board. They are suitable for embedded programming enthusiasts,
Linux and Android gadget fans (they can just use the board as a media center or fully functional
Linux-PC, for instance) and also professionals (since its low cost makes it very good solution for
application-orientated embedded systems). The main usage of the board is software embedded
development without the urge of understanding perfectly the hardware.
The strong points of the boards are the processor speed, the small form factor and the low price-to-
productivity ratio. The presence of native SATA and Ethernet controller and built-in battery charger
circuit allows the development of a wider range of products, compared to typical embedded Linux
boards. The A 0-OLinuXino-MICRO is a mature product – a lot of experience and projects are
already available such as GPIO, UART, I C, SPI, CAN libraries and examples. The A 0 chip is also
very well known and well supported (including in mainline u-boot and kernel).
Customers have full access to the technical documentation of the board. The software is released
under General Purpose License and the board is considered open-hardware – all schematics and
board design files are available to the customer under the Creative Commons Attribution-
ShareAlike 3.0 Unported License.
1.3 Board variants
The board has six board variants. The base version of the board, that comes with NO extra flash
memory, and works in the commercial temperature range is named A20-OLinuXino-MICRO. The
base version is usually sufficient for research and development (unless your project specifically
requires industrial temperature range and extra flash memory storage).
You might find a comparison table of the different board variants below:
Board variant Extra
flash
Type of
flash
Size of
flash
Boot Linux from flash
memory
Operating
temperature
range
A 0-OLinuXino-MICRO No - - - 0°C – 70°C
A 0-OLinuXino-MICRO-IND No - - - -40°C – 85°C
A 0-OLinuXino-MICRO-e4GB Yes eMMC 4GB Yes, after install script 0°C – 70°C
A 0-OLinuXino-MICRO-e4GB-IND Yes eMMC 4GB Yes, after install script -40°C – 85°C
A 0-OLinuXino-MICRO-n4GB Yes NAND 4GB Yes, after install script 0°C – 70°C
A 0-OLinuXino-MICRO-n8GB Yes NAND 8GB Yes, after install script 0°C – 70°C
The different versions of the boards can be determined by the suffixes after the base A 0-
OLinuXino-MICRO name, different names determine different version. The suffixes indicate three
things:
i) type of flash (“e” stands for eMMC; “n” stands for “NAND”; if there is flash memory at all)
ii) size of flash (“4GB” or “8GB”)
iii) whether the board uses industrial temperature grade components (when “IND” suffix is present)
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The prices for different board versions are also different. These four versions with extra flash
memory are named: A20-OLinuXino-MICRO-e4GB, A20-OLinuXino-MICRO-e4GB-IND,
A20-OLinuXino-MICRO-n4GB, and A20-OLinuXino-MICRO-n8GB. The name consists of the
type of the memory and the size of the memory – suffix “e4GB” stands for eMMC type of flash
with 4GB of size; “n4GB” stands for NAND type of flash with 4GB of size; “IND” stands for a
board with industrial temperature range components.
The other Olimex boards with close characteristics are the ones with A13 and A10 microcontrollers.
The A13 boards feature a generation older processor but since they have been longer on the market
they might have better Linux and Android support. The A10 boards feature single (than A 0)
processor core but they are more energy efficient making them better choices for handheld devices
and devices requiring power efficiency. A more powerful chip than the A 0 is used in the design of
A64-OLinuXino.
For projects and designs that require smaller form factor good alternatives to A 0-OLinuXino-
MICRO are: A 0-OLinuXino-LIME , A 0-OLinuXino-LIME, A 0-SOM-EVB, A 0-SOM 04-
EVB. For more powerful and recent designs consider the A64-OLinuXino board.
1.4 Board version used in the manual
Board from revision J was used while writing this document. It is possible that they are outdated so
it is always recommended to download the latest sources from the GitHub page of the board.
1.5 Organization
Each section in this document covers a separate topic, organized as follows:
–Chapter 1 is an overview of the board usage and features
–Chapter provides a guide for quickly setting up the board and software notes
–Chapter 3 contains the general board diagram and layout
–Chapter 4 describes the component that is the heart of the board: the A 0 – Allwinner
processor
–Chapter 5 is an explanation of the control circuitry associated with the microcontroller
–Chapter 6 covers the connector pinout, peripherals and jumper description
–Chapter 7 provides the schematics and the dimensions of the board
–Chapter 8 contains the revision history, useful links and support information
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CHAPTER 2: ETTING UP THE OLINUXINO BOARD
2. Introduction to the chapter
This section helps you set up the OLinuXino development board for the first time. Please consider
first the electrostatic warning to avoid damaging the board, then discover the hardware and software
required to operate the board.
The procedure to power up the board is given, and a description of the default board behavior is
detailed.
2.1 Electrostatic and electrical polarity warning
This product is shipped in a protective anti-static package. The board must not be exposed to high
electrostatic potentials. A grounding strap or similar protective device should be worn when
handling the board. Avoid touching the component pins or any other metallic element.
Ensure that your development board gets attached to properly working hardware. For example, it is
common for cheap HDMI monitors to lack grounding. Avoid TVs which have no grounding on their
power supply cable! If you can’t avoid them try to add the grounding yourself, if this is not possible
please use insulation products like USB-ISO to save your development board from potential over
voltage.
If you connect other electrical devices to the A 0 board make sure that they have equal electrical
polarity. For example, when you connect an HDMI cable between a TV and the board it is a good
idea to have them both connected to the same electrical source (to the same utility power socket).
This might be said for a serial cable connected between a PC and the board's DEBUG port.
In rare cases different polarity might cause hardware damage to the board.
2.2 Requirements
In order to set up the A 0-OLinuXino-MICRO optimally one or more additional items may be used.
They might be generally placed in three categories:
Required – items that are needed in order to achieve minimum functionality;
Recommended – items that is good to have in order to be able to interact with the most important
of the features of the board;
Additional – items that provide access to additional features or expand the features of the board.
Required items:
- USB type A to USB mini cable – to connect to a personal computer; used for powering the board
and uploading new Android image to the NAND memory (if your board has 4GB NAND)
- Input device – either a mouse/keyboard or touchscreen LCD
- Output device – either HDMI cable + native HDMI monitor/screen/projector; or USB-SERIAL-
CABLE-F + personal computer (for Linux and/or Android debugging); or OLIMEX LCD (TS)
display + 40-pin CABLE-IDC40-15cm; or A 0-VGA-CABLE + VGA monitor/screen/projector
- SD card with compatible image – if you have the board version with NO additional NAND
memory you will need it to use one of the images available.
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Recommended items:
- External USB hub – to split the USB_HOST mounted on the board; you need that to connect more
USB devices
- External power supply unit – (7- 4)V DC , 5W(10V @ 0.5A) required – for optimal power;
- USB-SERIAL-CABLE-F – for Android/Linux debugging on UART0
- CABLE-IDC40-15cm – cable used for LCD_CON ↔ Olimex LCD display
- Adapter cable for the 6-pin VGA connector to standard VGA 15-pin connector
Additional items include:
- Audio device for HEADPHONES jack
- Ethernet cable for wired Ethernet
- A number of extension modules that can add functionality or interface to the board on the UEXT
connector; these can be explored here: https://www.olimex.com/Products/Modules/
Some of the above-suggested items can be purchased by Olimex, for instance:
SY0612E – reliable power supply adapter 50Hz (for EU) 1 V/0.5A for A 0-OLinuXino-MICRO
SY0612E-CHINA – cheaper power supply adapter 50Hz (for EU) 1 V/0.5A for A 0-OLinuXino-
MICRO
A20-Android-SD – a tested class 10 micro SD card with the latest (by the time of leaving the
Olimex facilities) official Android release
A20-Debian-SD – a tested class 10 micro SD card with the latest (by the time of leaving Olimex
facilities) official Debian Linux release
USB-SERIAL-CABLE-F – USB serial console cable female
USB-MINI-CABLE – standard USB type A to USB type mini cable
A20-VGA-CABLE – adapter from 6-pin connector to 15-pin one
CABLE-IDC40-1 cm – cable for LCD to LCD_CON connection
LCD-OLinuXino-4.3TS – low-cost 4.3'' LCD display with touchscreen component – 480× 7
LCD-OLinuXino-7TS – low-cost 7'' LCD display with touchscreen component – 800×480
LCD-OLinuXino-10TS – low-cost 10.1'' LCD display with touchscreen component – 10 4×600
LCD-OLinuXino-1 .6 – low-cost 15.6'' LCD display with touchscreen component – 10 4×600
LCD-OLinuXino-1 .6FHD – low-cost 15.6'' LCD display with touchscreen component –
19 0×1080
SATA-HDD-2. - 00GB – 5GB .5'' SATA hard disk
SATA-CABLE-SET – cables that allow the connection of a .5'' hard disk to the board
ALUMINIUM-HEATSINK-20×20×6MM – heatsink radiator for better processor heat dissipation
For boards revision J or newer; the voltage applied to the power jack should be (6-16)V for older board revisions
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2.3 Powering the board
There are four possible ways of powering A 0-OLinuXino-MICRO – via external supply providing
7- 4V DC3 at the power jack, from 5V USB port via USB_OTG connector, from 3.7V Li-Po battery
via the LIPO_BAT connector, from 5V source applied to 5VEXT test pad at the bottom of the board
and any GND. Note that the board consumes around 300mA of current at 1 V when there are no
peripherals connected to the USB hosts, so make sure the power supply is able to provide at least
500mA before plugging. Depending on your preferred way of powering you might need additional
hardware.
The preferred way of powering the board is via the PWR jack with 7- 4V DC with a power of at
least 5W (usually 6Vx1A, 1 Vx0.5A, etc.). This will make the board fully powered and able to
power all the peripherals connected to it.
Important: Not all USB ports would be able to provide enough power for the board. Try using
another USB port or a cable of higher quality. If you have to use USB for powering, consider
externally powered USB port. The best practice is not to count on the mini USB-OTG as a single
power source!
The absolute maximum current available for the board and peripherals when the power supply is
supplied via USB-OTG connector is 900mA (no matter how much current you have available,
AXP 09 would output no more than 900mA). Of course, a big part of the current is required for the
board itself (without anything extra attached)! For comparison, when the power jack is used to
power the board – the typical current available after the AXP 09 is 500mA!
Note that when powering the board from the USB_OTG, the power provided might be insufficient
to also power a bigger LCD connected to the LCD_con. However, this power option is capable of
driving the board when using external display connected to the HDMI connector.
The typical consumption of A 0-OLinuXino-MICRO is between 100mA and 3 0mA depending on
the current load and the power voltage applied.
If the board has entered power-down state you can bring it back without restart using the
PWR_BUT. The PWR_BUT is also used to start the board when powered from a Li-Po battery on
the battery connector.
Sometimes when starting Android it is possible the board to enter battery save mode even before
booting fully. Especially, if you have turned off the board without quick boot mode enabled. In this
case you should press the PWR_BUT for at least 5 seconds which would allow the board to start.
For the European customers we sell two power supply adapters, please check chapter . . We also
sell USB OTG to USB type A cables if you lack such.
Note that it is normal that when the board is powered some integrated circuits might appear hotter
than others. This is perfectly normal for some chips – for instance – voltage regulators and the main
processor.
3 For boards revision J or newer; the voltage applied to the power jack should be (6-16)V for older board revisions
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2.4 Prebuilt software
The boards comes with no software uploaded. The board versions with extra flash memory also
come blank. Typically, the boards with NAND flash memory have the boot regions fixed, allowing
easier Linux install (eMMC boards don't need such preparation).
You can download the latest Linux Debian or Android image from the wiki article of the board and
download it to a microSD card. You can also install the Linux to the flash memory via install script.
If your board has extra flash memory and you want to boot Android from it refer chapter 6.1.1
USB-OTG communication (NAND firmware repair/update).
The default super user and password combination for the official Linux images is: “root” –
”olimex” and the GUI runs under user “olimex” with password “olimex”.
2.5 Button functions
The bellow three buttons usually are supported under both Android and Debian:
PWR_BUT – used to perform software turn off, software turn on; used to turn on board when
powered by battery – has to be held down for at least couple of seconds to perform each action;
RESET – used for hardware reset of the board – it is not recommended to reset the board this way;
RECOVERY – used to wake up the board from sleep
The following buttons represent functions in the Android (it is possible that not all Android
applications take advantage of the buttons, in such case the button would serve no purpose for that
application):
VOL+ – increases the volume
VOL- – lowers the volume
MENU – brings up the main menu
SEARCH – brings up search feature
HOME – shows the home screen; note that HOME is also used to enter bootloader mode for
firmware update
ESC – used to navigate away of a menu
ENTER – to select a choice
It is not recommended to disconnect the power supply (either the USB or the power jack) before
turning off the Android from the either the menus or by holding PWR_BUT. This might lead to file
system corruption and would require re-writing the image on the flash memory.
ow to restore the Android image might be found in chapter “6.1.1 USB-OTG communication
(NAND firmware repair/update)”.
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2.6 Interacting with the board
The typical and recommended way of interacting with a stand-alone A 0-OLinuXino-MICRO
board is via a 3.3V serial-to-USB cable connected to a personal computer. Such cables are common
and easy to find. Olimex also distributes such cables. Even if you already have such a cable or you
decide to purchase it elsewhere it is advisable to check these product pages as a reference:
https://www.olimex.com/Products/Components/Cables/USB-Serial-Cable/USB-Serial-Cable-F/
https://www.olimex.com/Products/Breadboarding/BB-CH340T/open-source-hardware
You need to connect the serial cable lines as follows: RX line to UART0-TX pin; TX line to
UART0-RX pin; GND to GND. Make sure that the serial cable is connected to your personal
computer and recognized properly after driver installation.
Then open a terminal program on the serial (COM) port which the cable is associated with.
After everything else is set, you would need to power the board as explained in “ .3 Powering the
board”.
In addition to the serial communication, you might also use one or more of the following mediums
to interact with the board:
1. a monitor via HDMI connector
. a monitor via the VGA connector and a VGA adapter
3. SSH via the mini USB connector trough a mini USB cable
4. SSH with a remote computer via LAN connector
5. a display via LCD_CON connector
More details on each of the connections might be found in the consequent sub-chapters.
Note that not all interface options are available for all images. Furthermore, some of the ways of
interaction are (obviously) not suitable for Android OS. The latest official Debian Linux image
should give you the most possible options of interfacing the board!
Using HDMI, LCD_CON or LAN might require additional configurations. Furthermore, it is
possible to corrupt the output settings over those interfaces and, thus, lose the output medium. In
such cases, you can always use the serial-to-USB cable as a reliable way to establish connection to
the board.
2.6.1 HDMI monitor
All official Debian and Android images for A 0-OLinuXino-MICRO have HDMI output by default.
The board would work out-of-the-box with a native HDMI monitor.
Make sure to use a tested HMDI cable.
The default HDMI resolution in the official images is 7 0p60 (1 80×7 0p at 60Hz). In order to
change that setting the video output on the LCD display you would need to run a configuration
script (if you use Debian Linux) or download a suitable image (if you use Android). Video output
settings are hard-coded in Android images.
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More information about the video output settings and the usage of video settings script might be
found in the next chapter “ .7 Changing the default image resolution”.
2.6.2 VGA monitor
All official Debian images for A 0-OLinuXino-MICRO have the option to for VGA video output
via the 6-pin VGA connector. If you wish to transform the custom 6-pin connector to a standard 15-
pin VGA connector you can either use wires or get a ready adapter called “A 0-VGA-CABLE”.
More information about the video output settings and the usage of video settings script might be
found in the next chapter “ .7 Changing the default image resolution”.
2.6.3 H via mini U B cable in Debian
The latest official Debian Linux image allows the use the USB_OTG connector for SSH connection
without the need of a LAN cable or a serial cable. You can use a mini USB cable connected
between your host PC and the on-board mini USB connector. For connection convenience there is a
DHCP server running specifically for USB0 interface. The DHCP server should give IP address to
the new USB0 interface of your host PC so you can make SSH connection from your PC to the
default board IP address of the USB0 interface – 19 .168. .1.
You can connect to the board using a mini USB cable and an SSH client (if you use Windows you
might use "puTTY", for example) at address 19 .168. .1.
For Windows operating system – upon connection, the board should show up in "Windows Device
Manager" as "RNDIS Ethernet Gadget". You might be asked to install a driver. The drivers can be
found online as "RNDIS driver" (Remote Network Driver Interface Specification). The drivers are
provided by Microsoft and they should be available for every Windows distribution – refer to the
respective files and articles provided by Microsoft on how to install the required drivers.
2.6.4 H via Ethernet
By default the board requests IP address from the network's DHCP server. You need to find what IP
address was assigned to the board before being able to access it over the network. Knowing the IP
address assigned allows you to connect to the board using an SSH client (for example “puTTY”)
then you have to use this address. You can change this policy or the address by editing
/etc/network/interface file.
Note that for internet connection you have to set your gateway address in /etc/network/interfaces
file and you have to set your DNS server in /etc/resolv.conf (for example “nameserver
19 .168.1.1”)
2.6.5 LCD display
One of the ways to interact with the board is via an external display (with or without touchscreen
component). The 40-pin male connector LCD_CON has the typical 0.1'' pin step. All Olimex
displays have corresponding 40-pin male connector. You would only need a 0.1'' female-female
cable for the hardware connection.
In order to get the video output on the LCD display you might need either to run at least once a
configuration script (if you use Debian Linux) or download a suitable image (if you use Android).
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Video output settings are hard-coded in Android images
More information about the video output settings and the usage of video settings script might be
found in the next chapter “ .7 Changing the default image resolution”.
2.7 Changing the default image resolution
Depending on the display or the screen you want to use with the A 0-OlinuXino-MICRO, you
might need to apply software changes to the prebuilt Android or Linux image.
The typical OlinuXino user would not need to edit the files, however.
To ease the process of changing the resolution we have compiled a number of Android images
for the Android users (with hard-coded video output settings). Alternatively, for Debian Linux
users, we have provided a shell script that can be executed in order to set preferred video
output and resolution.
For Android that you boot from the NAND memory you would need an image suitable for the
specific resolution. Download locations to such images might be found at the wiki article for the
A 0 board here: https://www.olimex.com/wiki/A 0-OlinuXino-MICRO.
For Linux Debian you would need to execute a shell script to be able to change the resolution. It is
very good idea to use a serial cable for connection to the board from a personal computer since in
this case you are dependent on a video resolution (a cable like USB-SERIAL-CABLE-F). When the
board boots type:
./change_display*
or
./change_display_A 0_OlinuXino.sh
and choose the resolution and the interface (LCD, HDMI or VGA).
The supported resolutions are:
For LCD:
1. 4.3" (480× 7 )
. 7" (800×480)
3. 10" (10 4×600)
For HDMI:
0. 480i
1. 576i
. 480p
3. 576p
4. 7 0p50
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5. 7 0p60
6. 1080i50
7. 1080i60
8. 1080p 4
9. 1080p50
10. 1080p60
For VGA: (note that the VGA signals are routed to custom 6 pin connector and you need to from
adapter to standard VGA connector, Olimex also sells such adapter cables)
0. 1680×1050
1. 1440×900
. 1360×768
3. 1 80×10 4
4. 10 4×768
5. 800×600
6. 640×480
7. 19 0×1080
8. 1 80×7 0
If you decide to edit the configurations yourself the easiest way would be to do it on the board. This
can be done offline too (manipulating the image located on the microSD card via a microSD card
reader). The tools for script.bin changing are located in /opt/sunxi-tools directory:
#cd /opt/sunxi-tools
#./chscr.sh
This will convert script.bin file from sdcard to script.fex file and the file will be opened using nano
editor. Now you can change the board modules and parameters, save the changes ("CTRL"+"X";
confirm with "Y") and exit ("CTRL"+"X" again) from nano editor.
#./wrscr.sh
this will convert script.fex to script.bin and the script.bin file will be written to the microSD card.
reboot
Reboot the board and the new settings would be enabled.
Alternatively, you can do the changes on the microSD card off the board. You would need to
remove the microSD card and explore it in a microSD card reader. You would need to edit the
configuration file script.bin and edit the settings inside. This file is usually located in Script.bin can't
be opened in the binary format so you would need to convert it to .fex file format first. There are
ready-to-use tools that convert script.bin <-> script.fex. Note that script.bin/fex contains
configuration settings and definitions not only for the video output but also for the pin descriptions
and names; power setting and much more. If you really want to modify and customize the default
images (to change port functions, port names, to disable specific peripherals) you would need to be
able to edit the script files. Please refer to the following web page for more information:
http://linux-sunxi.org/Fex_Guide
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2.8 Connecting a display and calibrating touchscreen
One of the ways to interact with the board is via an external display (with or without touchscreen
component). The 40-pin male connector LCD_CON has the typical 0.1'' pin step. All Olimex
displays have corresponding 40-pin male connector. You would only need a 0.1'' female-female
cable for the hardware connection.
All LCD displays made by Olimex have at least a 0.1'' LCD connector. Going for an LCD output
you would also need need and a cable to attach the display to the board. The cable is sold separately.
After the hardware connection is established, you need to execute shell script that would change the
video output of the board to fit the screen (refer to previous chapter).
The displays recommended for the board at the moment of writing might be found in the table
below:
Display name Size of
display
in inches
Native
resolution
in pixels
Official
Debian image
support
Official
Android image
support
Link to product
page
LCD-OlinuXino-4.3TS 4 3 480×272 Yes No Product page
LCD-OLinuXino-7 7 800×480 Yes Yes Product page
LCD-OLinuXino-7TS 7 800×480 Yes Yes Product page
LCD-OLinuXino-10 10 1 1024×600 Yes Yes Product page
LCD-OLinuXino-10TS 10 1 1024×600 Yes Yes Product page
LCD-OLinuXino-15.6 15 6 1366×768 Yes No Product page
LCD-OlinuXino-15.6 HD 15 6 1920×1080 Yes No Product page
The displays whose names contain “TS” - include a resistive touch screen component.
The cable used for connection depends on the specific board you are using and more specifically it
depends on the pitch of the LCD connector of the board. We have two cables – both 40-pins ones
but one for the bigger pitch (0.1'') and the other for the smaller one (0.05''). Each of the displays
listed in the table above has two connectors suitable for both cables:
CABLE-IDC40-15cm – 15cm long cable suitable for 0.1'' step connectors – Product page
CABLE-40-40-10CM – 10cm long cable suitable for 0.05'' step connectors – Product page
2.8.1 Android toucshcreen calibration
Calibrating a touchscreen component under Android is pretty straightforward from the Android
application.
Important: initially the boards are calibrated for a specific display and resolution. If you re-write the
image (no matter whether the SD card or the NAND memory) you might need to use a mouse to
calibrate the display initially. It might be impossible to calibrate it only by using the touch
component over the display.
2.8.2 Debian touchscreen calibration
Navigate to the system menu and then select "Preferences" -> "Calibrate Touchscreen". Follow the
on-screen prompts and remember to save the settings in the xorg.conf.d folder as suggested.
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If there is no “Calibrate Touchscreen” tool, then you are using older official Linux image and you
should execute “ts_calibrate” command, logged as user “olimex” (“su olimex”). The password is
also “olimex”.
The touchscreen calibration under Debian is detailed in the following wiki article:
https://www.olimex.com/wiki/Touch_calibration_official_images
2.9 GPIO under Debian
You can read data from a given GPIO port. The logical ranges are usually as follows:
0V-1V for LOW (or 0)
.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!
The algorithms for writing a value to a GPIO port and reading such a value are pretty similar. The
usage of GPIO ports follows the algorithm (we would use GPIO #49 for demonstration purposes):
1. Export GPIO 49:
echo 49 > /sys/class/gpio/export
Note that you can export GPIOs in range with:
for i in `seq 1 1 230`; do echo $i > /sys/class/gpio/export; done
. Set input/output GPIO 49
.1 Set input:
echo "in" > /sys/class/gpio/gpio49_ph9/direction
. Set output:
echo "out" > /sys/class/gpio/gpio49_ph9/direction
3. Set value or read value GPIO 49
3.1 Set value:
echo 0 > /sys/class/gpio/gpio49_ph9/value
echo 1 > /sys/class/gpio/gpio49_ph9/value
3. Read input:
cat /sys/class/gpio/gpio49_ph9/value
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4. Unexport GPIO 49 when finished
echo 49 > /sys/class/gpio/unexport
A very good document on GPIO usage might be found here:
http://www.py6zgp.com/download/A 0-GPIO.pdf – the document was created by Dr. Guido Pelz.
2.10 I2C and PI under Debian
I C and SPI are both supported in the latest Debian releases. There is respective kernel support for
both. There is a python module called pyA 0 might be found here:
https://pypi.python.org/pypi/pyA 0
At the same web address you would also find a set of examples on how module is used.
2.11 oftware support
We maintain Linux and Android images for SD card which might be downloaded for free and
modified as the user wishes. The latest images and updates are featured at the wiki article of the
device: https://www.olimex.com/wiki/A 0-OLinuXino-MICRO.
We usually try to provide details on how to build the Linux and the Android images at our
wordpress page: http://olimex.wordpress.com/.
Another useful place is the Olimex forums where a lot of people share their experience and advice:
https://www.olimex.com/forum/
Additional Android and Linux support and features are added overtime. The Linux support is a
work-in-progress and you should not expect full Linux support after the initial volume of such
boards have become available on the market. If you are in a hurry consider the older OLinuXino
designs (which have almost everything supported, have examples available and so on).
You are more than welcome to send or share your suggestions and ideas at our e-mail, the public
forums or irc channel. We would attempt to help in almost every case. We listen to the feedback and
if the majority of users suggest a software change or update we try to implement such. Customer
feedback is very important for the overall state of the software support. However, do not expect full
Linux or Android software support.
We can share our experience. We can give you full details for things we have tried. We can point
you to a resource or a guide. We can give you general directions to solving a specific problem or
places to look for more information. However, we won’t install a piece of software for you or write
custom program for you. We won't provide a specific software solution to a specific software
problem.
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CHAPTER 3: A20-OLINUXINO-MICRO BOARD DE CRIPTION
3. Introduction to the chapter
Here you get acquainted with the main parts of the board. Note the names used on the board might
differ from the names used below to describe them. For the actual names check the A 0-
OLinuXino-MICRO board itself.
3.1 Layout (top view)
The picture below shows the initial revision of A 0-OLinuXino-MICRO. Please note that the
NAND memory is present only in the 4GB version of the board.
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3.2 Layout (bottom view)
At the bottom of the board there are mainly buttons and the large SD/MMC connector.
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