OLIMEX A20-OLINUXINO-LIME2 User manual

A20-OLINUXINO-LIME2
and
A20-OLINUXINO-LIME2-4GB
Open-source single-board Android/Linu mini-computer
USER’S MANUAL
Document revision G, September 2017
Designed by OLIMEX Ltd, 201
All boards produced by Olimex LTD are ROHS compliant

OLIMEX© 017 A 0-OLinuXino-LIME user's manual
DISCLAIMER
© 017 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-LIME2 AND A20-OLINUXINO-LIME2- GB. THEY
ARE CONSIDERED SUITABLE ONLY FOR, RESPECTIVELY, A20-OLINUXINO-LIME2
OR A20-OLINUXINO-LIME2- GB.
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Table of Contents
DISCLAIMER ......................................................................................................................................
CHAPTER 1: OVERVIEW .................................................................................................................. 5
1. Introduction to the chapter ........................................................................................................... 5
1.1 Features ...................................................................................................................................... 5
1. Target market and purpose of the board ..................................................................................... 6
1.3 Board variants ............................................................................................................................ 6
1.4 Board version used in the manual .............................................................................................. 7
1.5 Document organization .............................................................................................................. 8
CHAPTER : SETTING UP THE OLINUXINO BOARD ................................................................. 9
. Introduction to the chapter ........................................................................................................... 9
.1 Electrostatic and electrical polarity warning ............................................................................. 9
. Requirements ............................................................................................................................. 9
.3 Powering the board .................................................................................................................. 11
.4 Button functions ....................................................................................................................... 1
.5 Interacting with the board ........................................................................................................ 1
.5.1 Serial connection at UART0 ........................................................................................................................... 1
.5. HDMI monitor ................................................................................................................................................ 13
.5.3 LCD display ................................................................................................................................................... 13
.5.4 SSH via mini USB cable in Debian ................................................................................................................ 13
.5.5 SSH via Ethernet connector ........................................................................................................................... 14
.6 Changing the default video output resolution .......................................................................... 14
.7 Connecting and calibrating a display ....................................................................................... 17
.7.1 Android calibration ......................................................................................................................................... 17
.7. Debian calibration .......................................................................................................................................... 18
.8 GPIO under Debian ................................................................................................................. 18
.9 I C and SPI under Debian ....................................................................................................... 19
.10 Software support .................................................................................................................... 19
CHAPTER 3: A 0-OLINUXINO-LIME BOARD DESCRIPTION ............................................... 1
3. Introduction to the chapter ......................................................................................................... 1
3.1 Layout (top view) ..................................................................................................................... 1
3. Layout (bottom view) ..............................................................................................................
CHAPTER 4: THE ALLWINNER A 0 MICROCONTROLLER ..................................................... 3
4. Introduction to the chapter ......................................................................................................... 3
4.1 The processor ........................................................................................................................... 3
4. Block diagram .......................................................................................................................... 4
CHAPTER 5: CONTROL CIRCUITY .............................................................................................. 5
5. Introduction to the chapter ......................................................................................................... 5
5.1 Reset ......................................................................................................................................... 5
5. Clocks ...................................................................................................................................... 5
5.3 Power supply circuit ................................................................................................................ 5
CHAPTER 6: CONNECTORS AND PINOUT ................................................................................. 6
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6. Introduction to the chapter ......................................................................................................... 6
6.1 UART0 interface ...................................................................................................................... 6
6. MicroSD card connector .......................................................................................................... 6
6. .1 SD/MMC1 slot ............................................................................................................................................... 6
6.3 PWR jack ................................................................................................................................. 8
6.4 USB_OTG ............................................................................................................................... 8
6.5 USB_HOST connectors ........................................................................................................... 30
6.6 Gigabit Ethernet ....................................................................................................................... 31
6.7 HDMI connector ...................................................................................................................... 3
6.8 SATA connector and power ..................................................................................................... 33
6.9 GPIO connectors ...................................................................................................................... 33
6.9.1 GPIO-1 (General Purpose Input/Output) 40pin connector ............................................................................. 34
6.9. GPIO- (General Purpose Input/Output) 40pin connector ............................................................................. 36
6.9.3 GPIO-3 (General Purpose Input/Output) 40pin connector ............................................................................. 37
6.9.4 GPIO-4 (General Purpose Input/Output) 0pin connector ............................................................................. 37
6.10 LCD_CON 40pin connector .................................................................................................. 38
6.11 Jumper description ................................................................................................................. 40
6.1 Additional hardware components .......................................................................................... 41
CHAPTER 7: SCHEMATICS ............................................................................................................ 4
7. Introduction to the chapter ......................................................................................................... 4
7.1 Eagle schematic ....................................................................................................................... 4
7. Physical dimensions ................................................................................................................. 43
CHAPTER 8: REVISION HISTORY AND SUPPORT .................................................................... 44
8. Introduction to the chapter ......................................................................................................... 44
8.1 Document revision ................................................................................................................... 44
8. Board revision .......................................................................................................................... 45
8.3 Useful web links and purchase codes ...................................................................................... 45
8.4 Frequently asked questions ...................................................................................................... 47
8.5 Product support ........................................................................................................................ 51
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CHAPTER 1: OVERVIEW
1. Introduction to the chapter
Thank you for choosing this OLinuXino single board computer from Olimex! This document provides a
user’s guide for the Olimex A 0-OLinuXino-LIME 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-LIME development board enables code development of applications running on
the A 0 microcontroller, manufactured by Allwinner Technology from China.
OLinuXino is an open-source, open-hardware project and all design files are available to the customer.
1.1 Features
The board has the following set of features:
•A 0 Cortex-A7 dual-core ARM Cortex-A7 CPU and dual-core Mali 400 GPU
•1GB DDR3 RAM memory
•1000MBit native Ethernet
•GB or 8GB NAND FLASH memory (available only on certain variants of the board)
•GB eMMC memory (available only on certain variants of the board)
•SATA connector with 5V SATA power jack
•Native HDMI interface with standard connector
•Capable of FullHD (1080p) video playback
•x USB Low-Full-High-Speed hosts with power control and current limiter
•USB-OTG with power control and current limiter
•LiPo Battery connector with battery-charging capabilities
•LCD row of pins (0.05'' step)
•160 GPIOs on four GPIO rows of pins (0.05'' step)
•MicroSD card connector
•DEBUG-UART connector for console debug with USB-SERIAL-CABLE-F
•Status LED
•Battery charge status LED
•Power LED
•KB EEPROM for MAC address storage and more
• BUTTONS with ANDROID functionality + RESET button
• mount holes
•5V input power supply, noise immune design
•PCB dimensions: (84 × 60)mm ~ (3.3 × .4)"
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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 LIME boards are a special kind of OLinuXino boards – they are as small as possible while
maintaining a remarkable stand-alone functionality. The strong points of these boards are the processor
speed, the small form factor and the low price-to-productivity ratio.
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 four major board variants. The difference in the suffix is based on the type and volume of
extra flash memory installed on the board. The base version of the board, that comes with NO extra flash
memory is named A20-OLinuXino-LIME2. These three variants with extra flash memory are named:
A20-OLinuXino-LIME2-e GB, A20-OLinuXino-n GB, and A20-OLinuXino-LIME2-n8GB. The
name consists of the type of the memory and the size of the memory – suffix “e GB” stands for eMMC
type of flash with 4GB of size; “n GB” stands for NAND type of flash with 4GB of size.
The e GB version comes with 4GB eMMC flash memory that expands the on-board storage available
and also allows booting the operating system without the need of a SD card. The eMMC memory comes
blank (you would have to upload desired operating system to the eMMC memory).
Exactly the same is the case with the n GB and n8GB variants. The n GB and n8GB versions come
with either 4GB or 8GB extra NAND flash memories expands the on-board storage available and also
allows booting the operating system without the need of a SD card. Note that these memories also come
blank (you would have to upload desired operating system to the NAND memory).
Currently, there is higher demand for boards with eMMC since seem to require less power, have longer
life, corrupt harder. Additionally, the eMMC memories that we use have an industrial temperature range
version.
Board variant Extra Flash Type of Flash Size of Flash Boot Linux from Flash
A 0-OLinuXino-LIME No - - -
A 0-OLinuXino-LIME -e4GB Yes eMMC 4GB Yes after install script
A 0-OLinuXino-LIME -n4GB Yes NAND 4GB Yes after install script
A 0-OLinuXino-LIME -n8GB Yes NAND 8GB Yes after install script
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A 0-OLinuXino-LIME looks similar to both A 0-OLinuXino-LIME and to A10-OLinuXino-LIME. The
major differences between A 0-OLinuXino-LIME and A 0-OLinuXino-LIME are:
1. LIME has gigabit Ethernet (GbE), compared to the standard 100Mb Ethernet of the LIME.
. LIME design provides double the RAM memory, compared to the LIME design (10 4 vs 51 ).
3. Much better routing of DDR3 memory.
4. Increased the number of layers from 6 in LIME to 8 in LIME .
5. Corrected pinout of the LCD connector (shields for LIME are not compatible with LIME )
6. The price tag
Due to the hardware differences listed above the Linux and Android distributions of the LIME and
LIME boards are not identical. Furthermore, some of the hardware extensions are not compatible with
both of the designs. For example, the A10-OLINUXINO-LIME-UEXT is not compatible with A 0-
OLinuXino-LIME board.
1.4 Board version used in the manual
Revision B boards and resources were 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
(https://github.com/OLIMEX/OLINUXINO/tree/master/HARDWARE).
Some peripherals, documents or software may be suitable for both the A 0-LIME and the A 0-LIME
designs but it is generally advised to use resources for the specific board.
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1.5 Document 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 processor
–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: SETTING UP THE OLINUXINO BOARD
2. Introduction to the chapter
This section helps you set up the 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
A 0-OLinuXino-LIME 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 USB-ISO to save your development board from potential over voltage.
If you connect other electrical devices to the LIME 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-LIME 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); can also be used to
access the Linux of the board
- 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)
- 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.
Recommended items:
- External USB hub – to split the USB_HOST mounted on the board; you need that to connect more USB
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devices
- External power supply unit – 5V DC, 5W required – for optimal power
- BOX-LIME – a metallic and aesthetic box specially made for the board that protects it from dust and
accidental short-circuits
- USB-SERIAL-CABLE-F – for Android/Linux debugging on UART0
Additional items include:
- Small heatsink for the processor – during long video playbacks the A 0 processor might heat up
- External .5'' SATA hard disk drive (proper cables sold separately)
- Ethernet cable for wired Ethernet
Important note on requirements:
The board works with .5'' SATA hard disks that can be powered by 5V source from the board! For the
3.5'' hard disks you would probably need to provide external 1 V supply.
It is a very good idea to have a USB-SERIAL-CABLE or similar cable since it allows you to:
1. Change display output settings for Debian easily
. Debug the board via any personal computer even if there are problems with the video output
Some of the above-suggested items can be purchased by Olimex, for instance:
SY0605E – reliable power supply adapter 50Hz (for EU) 5V/1A for A 0-OLinuXino-LIME
SY0605E-CHINA – cheaper power supply adapter 50Hz (for EU) 5V/1A for A 0-OLinuXino-LIME
A20-LIME-ANDROID-SD – a tested class 10 micro SD card with the latest (by the time of leaving the
Olimex facilities) official Android release
A20-LIME-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 – female USB serial console cable
USB-MINI-CABLE – standard USB type A to USB type mini cable
A20-OLINUXINO-LIME2-UEXT – GPIO adapter which makes LIME GPIOs available in breadboard
friendly 0.1" step connectors, needed if you want to connect an older Olimex-made display to the board
(newer displays listed below have 0.05'' step connector)
CABLE- 0- 0-10CM – 0.05'' step cable for connecting a new display to the board
LCD-OLINUXINO- .3TS – low-cost 4.3'' LCD display with touchscreen component – 480× 7
LCD-OLINUXINO-7TS – low-cost 7'' LCD display with optional touchscreen component – 800×480
LCD-OLINUXINO-10TS – low-cost 10'' LCD display with optional touchscreen component –
10 4×600
LCD-OLINUXINO-15.6 – low-cost 15.6'' LCD display – 1366×768
LCD-OLINUXINO-15.6FHD – low-cost Full HD 15.6'' LCD display – 19 0×1080
CABLE-IDC 0-15cm – 0.1'' step cable for connecting an LCD to LCD_CON
SATA-HDD-2.5-500GB – 500GB .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
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2.3 Powering the board
There are three possible ways of powering A 0-OLinuXino-LIME – via external supply providing 5V
DC at the power jack, from 5V USB port via USB_OTG connector or from 3.7V Li-Po battery via the
LIPO_BAT. Note that the board might consume up to 650mA of current at 5V when there are no
peripherals connected to the USB hosts. Make sure your power supply is able to provide at least 1A
before. Depending on your preferred way of powering you might need additional hardware.
Important: Not all USB ports would be able to provide enough power for the board. Try using another
USB port/USB hub or a cable of higher quality.
If you have an LCD display connected to the board or external .5'' hard disk then the USB will NOT be
sufficient source of power.
The best practice is to never count on the mini USB-OTG as a single source of power for the board!
The preferred way of powering the board is via the PWR jack with 5V DC. This would make the board
fully powered and able to power all the peripherals connected to it.
Note that when powering the board from the USB_OTG, the current 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-LIME is between 400mA and 650mA depending on the
current load.
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 button 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.
The default username/password combination for the default Linux image on the SD card (if purchased) is:
root/olimex.
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.
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2.4 Button functions
The bellow three buttons usually are supported under both Android and Debian:
PWR – 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 5 seconds to perform each action
RESET – used for hardware reset of the board
RECOVERY – used to wake up the board from sleep
It is recommended to always make a soft “turn off” of the board. If that is not possible then please hold
PWR button down for a few seconds to “turn off the board”. Then you are free to remove the power
supply. If you disconnect the power supply (either the USB, the battery or the power jack) before turning
off the board you may corrupt your SD card. If you have placed NAND memory you can corrupt the
image on the NAND memory.
2.5 Interacting with the board
There are five typical ways to interact with A 0-OLinuXino-LIME . You can interact with A 0-
OLinuXino-LIME and:
- a personal computer or another board via UART0 and a serial ow cable
- an HDMI monitor via the HDMI connector and an HDMI cable
- an LCD display via LCD_CON connector and 0.05'' step 40-pin cable
- a personal computer or another board via the mini USB connector and a mini USB cable, using SSH
protocol
- a personal computer via the Ethernet connector and a LAN cable, using SSH protocol
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 official Debian 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. In such cases, you can always
use the serial cable USB-SERIAL-CABLE-F as a reliable way to establish connection to the board.
2.5.1 Serial connection at UART0
The default and recommended way to communicate with the Linux operating system of the board is using
the serial connection available at UART0 connector. You would probably need an USB<->SERIAL cable
for such a connection. Even if you intend to use HDMI or LCD it is a good idea to have it as a basis – the
video output is not always reliable and if you set wrong display settings you would be unable to recover
the software without an alternative connection.
We distribute a ready-to-use cable. Even if you already have such a cable or you decide to purchase it
elsewhere it is advisable to check this product page for a reference: Product page
Note that the levels at board's UART0 are in CMOS level (3.3V) and you would need a convertor to bring
them to the TTL level of your computer or cable! That is true for the RX and TX also! You would need to
consider that if you decide to make your own cable.
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The cable probably needs drivers – after successful driver installation a COM port device would show up
in the hardware manager of your computer. Then you would need to connect the serial cable wires to the
board as follows: RX line to UART1-TX pin; TX line to UART1-RX pin; GND to GND. The last pin of
UART1 connector is named 3.3V and it can be used to power the board, if you have other ways of power
the board leave 3.3V pin unconnected! Be careful to avoid the connection to the serial cable else there
would be a short-circuit. 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. The settings
for the connection are 115 00 baud, 8-N-1. After everything else is set, you would need to power the
board as explained in “ .3 Powering the board”.
2.5.2 HDMI monitor
The board comes equipped with HDMI connector to connect to a compatible monitor. However, there is
no cable included. Make sure to use a tested HMDI cable.
All official Debian and Android images for A 0-OLinuXino-LIME have HDMI output enabled by
default. The board should work out-of-the-box with a native HDMI monitor.
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 but there are ways to edit the images. You might find more information about editing pre-
built Android images at this wiki article: how to edit prebuilt Android images.
More information about the video output settings and the usage of video settings script might be found in
chapter “ .6 Changing the default image resolution”.
2.5.3 LCD display
Various LCD displays can be attached to A 0-OLinuXino-LIME and used to interact with the board.
Depending on the display chosen and whether you attempt to run Debian Linux or Android additional
video settings configuration may be required. It is always a good idea to have one of the other connection
options available as back-up (in case the video output settings need modification).
For more information refer to chapter “ .7 Connecting and calibrating a display”.
2.5.4 SSH via mini USB 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
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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.
2.5.5 SSH via Ethernet connector
SSH protocol allows you to login remotely to the command-line interface of the A 0-OLinuXino-LIME
board. You would need an active Ethernet connection to the board.
The newest images have a configuration that allows SSH via the Ethernet connector. The static IP address
to access the board is 19 .168.1. 54
2.6 Changing the default video output resolution
Depending on the display or the screen you want to use with the A 0-OLinuXino-LIME , 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-LIME .
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_a20_olimex.sh
It looks like this:
Then the main menu of the video configuration script shows up and you can select the desired interface
(LCD, HDMI or VGA):
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The supported resolutions for LCD:
1. 4.3" (480× 7 )
. 7" (800×480)
3. 10" (10 4×600)
The supported resolutions for HDMI:
0. 480i
1. 576i
. 480p
3. 576p
4. 7 0p50
5. 7 0p60
6. 1080i50
7. 1080i60
8. 1080p 4
9. 1080p50
10. 1080p60
The supported resolutions for VGA (please note that there is no VGA connector and you would need to
install additional hardware - more instructions on the VGA signals might be found in the chapter 6):
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
Chose the resolution that suits you and reboot the board.
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).
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The tools for script.bin changing are located in the image. First convert the binary to text with:
bin2fex /boot/script.bin /boot/script.fex
This will convert script.bin file from sdcard to script.fex file. Then open the file with nano text editor:
nano /boot/script.fex
Edit the file as you want (pin assignments etc) and save the changes and exit. The different options for the
script are explained here: Please refer to the following web page for more information: http://linux-
sunxi.org/Fex_Guide
IMPORTANT! ADJUSTING SCRIPT.BIN WITH IMPROPER VALUES MIGHT BREAK YOUR
DEBIAN IMAGE AND IT IS ALWAYS RECOMMENDED TO KEEP A BACK-UP OF YOUR
DEFAULT SCRIPT.BIN
When done with editing save the changes, exit nano and convert the text file back to binary format with
fex bin tool, type:
fex2bin /boot/script.fex /boot/script.bin
Finally, reboot the board:
reboot
Reboot the board and the new settings would be applied.
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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2.7 Connecting and calibrating a display
One of the ways to interact with the board is via an external display (with or without touchscreen
component). If you want to use a display for video output from the LIME board the best way is to use the
LCD_CON row of pins. The step between the pins of the connector is the smaller one – only 0.05''
(compared to 0.1'' of bigger boards).
Newer displays made by Olimex have both 0.1'' and 0.05'' step connectors. 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.
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
further below has two connectors suitable for both cables:
CABLE-IDC40-6cm – 6cm 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
The displays recommended for the board at the moment of writing might be found in the following table:
Display name Size of
display
in inches
Native
resolution
in pixels
fficial
Debian image
support
fficial
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 1024×600 Yes Yes Product page
LCD-OLinuXino-10TS 10 1024×600 Yes Yes Product page
LCD-OLinuXino-15.6 15.6 1366×768 Yes No Product page
LCD-OLinuXino-15.6FHD 15.6 1920×1080 Yes No Product page
The displays whose names contain “TS” - include a resistive touch screen component.
2.7.1 Android calibration
Calibrating a display 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 via touching the display.
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2.7.2 Debian calibration
The command that allows calibrating in Debian Linux is:
ts_calibrate
The default Debian setup is made with settings for HDMI 7 0p/60Hz. If you want to change some other
LCD, VGA or HDMI resolution then you have to start script file in /root directory.
If the problem is under Debian Linux make sure you are properly logged in the XFCE 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 password: olimex
calibrate the touch screen and reboot the board
#sudo reboot
2.8 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
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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
4. Unexport GPIO 49 when finished
echo 49 > /sys/class/gpio/unexport
A helpful document on A 0's GPIO usage might be found here: http://www.py6zgp.com/download/A 0-
GPIO.pdf – the document was created by Dr. Guido Pelz.
Alternatively, you might also use the Python script mentioned in the next chapter.
2.9 I2C and SPI under Debian
I C and SPI are both supported in the latest Debian releases. There is a python module called
pyA 0Lime , which also might be found here: https://pypi.python.org/pypi/pyA 0Lime
At the same web address you would also find information on how the library is used.
2.10 Software 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-LIME .
We usually try to provide details on how to build the Linux and the Android images at our GitHib page:
https://github.com/OLIMEX/OLINUXINO/tree/master/SOFTWARE/A 0
Another useful place is the Olimex forums where a lot of people share their experience and advice:
https://www.olimex.com/forum/
The official images are a constant work-in-progress – newer releases are packed with better hardware
support, newer kernels and extra features.
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
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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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