A20-SOM user`s manual
Contents
1. 6 5 6 GPIO 6 General Purpose Input Output 10pin connector This connector was added in hardware board revision C It is missing in board revisions A and B It has some points that might be used as test pads Also couple of signals that might be used to debug the power supply Fin signal nane processor pint Pin Siena1 name processor pine apm me E jeu 3pm yn ww mz ec am ejue sackue ema esour cones row aao efe nst ema ez leen enaner Page 29 of 41 OLIMEXO 2015 A20 SOM user s manual 6 6 LCD CON 40pin connector The LCD CON pins are led out on a separate 40pin connecter for the ease of connecting an LCD The step of the connector of A20 SOM is still 0 5 We have tested the ability of the board to interact with such a display They allow the user to attach additional hardware check readings or perform hardware debug Important you would probably need an additional adapter board and two different 40PIN ribbon cables to connect an Olimex display and the LCD CON The evaluation board RK3188 SOM EVB provides a 0 1 step LCD connector which eases the hardware interfacing between the board and the display The LCD connector is suitable but not plug and play due to the different pin step for a number of Olimex displays and touchscreen panels with different native resolution the smallest available is the 4 3 one called LCD OLinuXino 42. For HDMI 480i 576i 480p 576p 720p50 720p60 1080150 1080160 NANRWNEROS Page 13 of 41 OLIMEXO 2015 A20 SOM user s manual 8 1080p24 9 1080p50 10 1080p60 For VGA VGA is available out of the box only in the A20 SOM A20 SOM EVB combination else additional hardware is required 1680x1050 1440x900 1360x768 1280x1024 1024x768 800x600 640x480 1920x1080 1280x720 CDJ OU P Ota CH Depending on the display or the screen you want to use with the A20 SOM you might need to apply software changes to the prebuilt Android or Linux image The easiest way would be to do it on the board itself but it 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 For the Debian Linux releases this means that you would need to edit the configuration file script bin and edit the settings inside This file is usually
3. step connectors Product page Page 15 of 41 OLIMEXO 2015 A20 SOM user s manual 2 8 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 only by using the touch component over the display 2 8 2 Debian calibration The command that allows calibrating in Debian Linux is ts_calibrate The default Debian setup is made with settings for HDMI 720p 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 LXDE 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 Page 16 of 41 OLIMEXO 2015 A20 SOM user s manual 2 9 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 featur
4. 3TS with native screen resolution of 480x272 through the 7 one named LCD OlinuXino 7TS with 800x480 to the 1024x600 10 1 LCD OLinuXino 10TS Note that the smallest display 4 3 480x272 is not suitable for the official Android images we provide Full list of recommended displays for the board might be found in chapter 2 7 Connecting and calibrating a display Lo pi us seo pu ipis Ju sies ka Lc ne een aaa uico ez ips ue npo deu adeo n njope ws mp Bus Lp pma hos ida hop ms 39955 ia mee en heo Bur nioak e alcove PB3 B14 a4 PB4 A13 mu jus ema isa Page 30 of 41 OLIMEXO 2015 A20 SOM user s manual 6 7 Jumper description Please note that two jumpers on the board are SMT type If you feel insecure of your soldering cutting technique it is better not to try to adjust the jumpers since it is possible to damage the board Board jumpers Controls whether the NAND memory Either CLOSED or module is enabled or disabled OPEN depending whether the board has 4GB NAND MEMORY MODULE If the jumper is closed than the NAND memory is operational By default it should be set properly for your board The jumper is used for internal testing It is not recommended to change its position When the jumper is closed it removes a circuit that handles
5. 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 A20 SOM board itself 3 1 Layout top view The picture below shows the top side of the A hardware revision of board and highlights the most important parts OLIMEX A20 SOM GPIO 1 GPIO 2 LCD CON E 1 2 mimm 2 y dENUSUNU L AN Wo xA RN v NA j An nu AAAJAAA AAA muli dL A A LJ ub P OM ETT p RAM DDR3 SEN KS e Ee Kc microSD o D 5 N D 2 jl Gute R9 stan i HD M m S 4 0137 azo o C6 C61 Ct9 C35 E RI e RMZ RNS RM6 RNS RN Feu C26 V C161 s AZO SO l B45 o Rev fi SUN 3 AMO E He dh E Ge Allwinner j EID D S i OLIMEX com In A20 UR A AAAA N GPIO 5 GPIO 4 GPIO 3 GPIO 1 GPIO 2 GPIO 3 GPIO 4 GPIO 5 and LCD CON are connectors with 0 05 step They are used to connect A20 SOM to A20 SOM EVB Please note that there might be differences in the layout of top of the board compared to the latest revision One of the notable changes introduced in hardware revision C of the design is the addition of GPIO 6 row of pinholes that provides easier access to some additional pins The general routing and memory positions are also adjusted Page 18 of 41 OLIMEXO 2015 A20 SOM user s manual CHAPTER 4 THE ALLWINNER A20 MICROCONTROLLER 4 Introduction to the chapter In this chapter is located the informatio
6. mounted atop A20 SOM EVB The sub chapters below deal with both scenarios 2 3 1 Stand alone powering If you use the board in stand alone mode e g it is neither attached to A20 SOM EVB nor to any other board of peripherals there are fewer options for powering it Consider that you might need additional cables or connectors You have the following options of powering the board 1 5V via UARTO header requires external 5VDC power source 2 5VEXT via GPIO 2 SVEXT pin 1 GND pin 2 and GPIO 4 SVEXT pin 1 GND pin 2 requires external 5VDC power source 3 BAT via GPIO 2 BAT pin 3 GND pin 74 requires external 4 2VDC battery 4 bV OTG PWR via GPIO 1 5V_OTG_PWR pin 5 GND pin 2 requires external 5VDC driven by any USB The default way of powering the board is using external power supply In that case you would need to provide 5V DC at the 5VEXT pin of UARTO connector You would also need to connect the GND pin of the same connector to the GND line of you supply The minimum power that your supply should be able to prove is 2 5W equivalent of 0 5A of current at 5V of voltage Note that there is no standard jack for the powering circuit but you might add own DC power jack Do not provide AC voltage to the A20 SOM board Do not provide more than 5V of voltage directly to the A20 SOM board Providing 12V would instantly cause permanent hardware damage Page 9 of 41 OLIMEXO 2015 A20 SOM user s manual Sometimes wh
7. other electrical devices to the SOM board make sure that they have equal electrical polarity For example when you connect a serial cable connected between a PC and the board s DEBUG port it is a good idea to have them both connected to the same electrical source to the same utility power socket In rare cases different polarity might cause hardware damage to the board 2 2 Requirements In order to set up the A20 SOM board optimally one or more additional items may be needed They might be generally placed in two 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 Note that if A20 SOM is mounted on A20 SOM EVB the requirements would be different The requirements below are for a stand alone use of A20 SOM Refer to A20 SOM EVB s user s manual for adjusted requirements Required items 5V external power supply with proper connectors A20 SOM has no power jack only powering pins BVEXT GND Output device USB SERIAL CABLE F personal computer with serial terminal program A20 SOM lacks other options for debugging you would need a serial cable that can work at the CMOS levels of the board s signals SD card with compatible image if you have the board version with NO additional NAND Page 8 of 41 OLIMEXO 2015 A20 SOM user s manual memory you will
8. 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 to download 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 google drive 2 Download and extract the latest official image from the Android section of the wiki A20 SOM article Make sure that the download link you visit clearly indicates that the image is suitable for the NAND memory since there are images suitable for microSD card also The images suitable for the microSD memory and those suitable for microSD card are different However the upload method is almost identical using PhoenixSuit 3 Go to firmware tab of the program and point to the already downloaded and extracted Android Page 39 of 41 OLIMEXO 2015 A20 SOM user s manual image 4 Disconnect the power supply and USB cable from the A20 board 5 Press and hold RECOVERY button apply power supply the requirement various depending on whether you use the board stand alone or on top of A20 SOM EVB release RECOVERY button 6 Connect USB cable to the mini USB connector 7 You will be asked for drivers for the bootloader Navigate to the folder where you extracted the PhoenixSuit and install the dr
9. the OLIMEX s GitHub repository https github com OLIMEX SOM tree master A20 You can download the whole repository as zip without having a GitHub account The part of the design that has the main microcontroller is considered proprietary design and design files would not be shared If you are looking for a schematic of an older revision of the board and it isn t available at our web site you may request it by the support e mail 7 2 Physical dimensions Note that all dimensions are in mils 18000mil eee es Boo FEEEEELELELLELETTELLE RE gt 8 E DE Er Dn20non 1953mil 2200mil Len LY RSR 108mil 3200mil Page 32 of 41 OLIMEX 2015 A20 SOM user s manual CHAPTER 8 REVISION HISTORY AND SUPPORT 8 Introduction to the chapter In this chapter you will find the current and the previous version of the document you are reading Also the web page for your device is listed Be sure to check it after a purchase for the latest available updates and examples 8 1 Document revision Document revision ae Nodified page A 08 10 14 Initial manual release Cleared duplicate information B 18 11 14 Updated the information about the LCD 7 15 displays C 26 11 14 Improved LCD display information 12 14 D 19 12 14 Adjusted for boar revision D changes 17 30 E 30 01 15 Fixed wrong information about the o inner pin of the power jack A 1 21 1 F 09 02 2015 Fixed information about
10. A e DI nl gt LA gt HB a radar ATULToa Tot mol br gt j N x x x B d md U0 NINIJIN Gicic i o o DO WO WI 27 UART6 TX oje 31 SPI2 MISO 33 SPI2 CLK 35 GPIO1 37 GP102 39 GP103 N Pin amp Signal name Pin dBvxr o aE qd SIE 0 NN TIWIO SDA 8 9PE7 CSIO D3 10 GIPEB CSIO DA E A3PPES CSIO DS tl d5PEIO CSI D6 16 a7 Peat cste_o7 EE Bunn E14 E 21 PB18 Twr1 SCK_ om 23PILMISO ai 25 sPza clk 26 2TUARTeCTX 0 28 29 TWI2 SCK 30 3iSPI2 MISO EN 33 SPI2 cLK EE 35apzo1_ 36 37 apr02_ 0 38 3e g103 29 Page 28 of 41 OLIMEXO 2015 A20 SOM user s manual 6 5 5 GPIO 5 General Purpose Input Output 40pin connector Pin Signal name Processor pin A17 PG5 12 SDC3 CMD 18 1 13 PG6 14 SDC3 CLK 18 15 PG7 16 PC16 CAM PWR EN M21 PG8 18 PC17 NWP PG10 n caso xen m BEER EE se see N iw N HB zziz z v o o Loo Lotleal to Dio DIaAIaATOaTO ef Kal Bas He ee O DWDINININI RR OJALO ya mj rm G i 5 juw oo Uu u u 5 zl IW T Dla a Ke es ka w O Nje oO eI 23 y 3 D m UJ N LA N D gt is CIioimieotOiOlmimnim Ne H N N VD TU DIS N N N N PC3 SATA PWR EN IS fend Bel foll fend ffe N N 2 nj 2 CY m G z vu J G e HG NO KA e
11. BLE F remember to refer to the wire color code The RX line of the cable GREEN wire should go to TX line of the target board the TX line of the cable RED wire should go to the RX line of the target board The BLUE wire should go to the target s GND line 6 3 MicroSD card connector The micro SD card slot is primarily used for booting the operating system The board works with micro SDHC cards up to 32GB of storage As a general precaution be careful with the SD cards you purchase There is a big percentage of fake cards due to the low effort required to counterfeit popular brands and the big demand for SD cards worldwide When in doubt try the same operation with another card from another brand Olimex sells microSD cards with Linux or Android images that have been tested please refer to chapter 2 2 Requirements Of course if you already have a large enough microSD card you can download the official Linux image from the wiki pages https www olimex com wiki A20 SOM When removing the card please make sure that you release it from the connector by pushing and NOT by pulling the card directly this can damage both the connector and the microSD card 6 3 1 SD MMC slot The schematic related to the SD MMC microSD connector is shown below SD MMC slot is a microSD card slot connector 77 77 4j located on the top of the board M 1Cr o S D This slot is typically used for booting the OS due e to the larg
12. OM EVB s web page is here https www olimex com Products SOM A20 A20 SOM EVB open source hardware Wiki article of the board https www olimex com wiki A20 SOM A place for general questions FAQ or friendly talk https www olimex com forum You can get the latest updates on the software at https github com OLIMEX SOM tree master A20 You may may join our IRC channel olimex 2 freenode net http webchat freenode net channels olimex The sunxi community is behind the Allwinner Linux support http linux sunxi org Main Page ORDER CODES A20 SOM the product for which this manual is about A20 SOM EVB A20 SOM 4GB a shield with all important peripherals HDMI port Gigabit interface SATA port Headphones jack Microphone jack Camera etc USB SERIAL CABLE F USB serial console cable female A20 SOM Android SD a tested class 10 micro SD card with the latest by the time of leaving the Olimex facilities official Android release A20 SOM REV D DEBIAN SD a tested class 10 micro SD card suitable for A20 SOM boards revision C or newer with latest by the time of leaving the Olimex facilities official Debian release A20 SOM DEBIAN SD a tested class 10 micro SD card suitable for A20 SOM boards revision A and revision B with latest by the time of leaving the Olimex facilities official Debian release LCD OLINUXINO 4 3TS low cost 4 3 LCD display with touchscreen component 480x272 LCD OLINUXINO 7TS low co
13. SrecVreecreseeeecwe eT KR ee eee EES PPR RRR ORR RR ERE EERE Se i 4 2 y BAAR AR HR GREEN ARR RAR RHR RARA GPIO 2 ei o e MO OD E ODAL DET RTT TET RH7 Eng RHE RMS 64 C61 C59 C35 C22 C26 A20 SOM R45 Mol R WK KCS7 Cgo te A C98 cga pwy cpro 4HHH OLIMEX COM UUER ERE RRER BREN EER EE 161 ive vni E Pee oye A20 SOM AND A20 SOM 4GB System on Module boards capable of Linux and Android boot USER S MANUAL Document revision I March 2015 Designed by OLIMEX Ltd 2015 lead free All boards produced by Olimex LTD are ROHS compliant OLIMEXO 2015 A20 SOM user s manual DISCLAIMER 2015 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 The hardware designs of A20 SOM and A20 SOM 4GB development boards are considered intellectual property to Olimex The hardware design files are considered copyright material and would not be distributed The hardware design of A20 SOM EVB development board is considered open source hardware The source design files are published online and accessible by everyone The so
14. VGA connector 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 Refer to the A20 SOM EVB s datasheet for more information on each connection Note that not all interface options are available for all images Furthermore some of the ways of interaction are 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 Page 11 of 41 OLIMEXO 2015 A20 SOM user s manual 2 6 Expanding the Debian file system space The provided official Debian images have constant size but you may want to use a bigger microSD card In case you don t know how to expand the file system space you can use the built in shell script for this task This way you can take advantage of the whole volume of your microSD card Type in the command prompt resize_sd sh dev mmcblk0 1 After that you need to reboot the board with reboot You can find the name given to the microSD card and its partition using fdisk l 2 7 Changing the default image resolution The method for changing the output video resolutions vari
15. a 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 reason for this alteration is the additional hardware that A20 SOM EVB it provides direct HDMI output and easier ways to connect peripherals to the board Generally the processors features are much easier to access 1 3 Features of A20 SOM The A20 SOM board has the following set of features Allwinner A20 dual core Cortex A7 processor each core typically running at 1GHz 1GB DDR3 memory AXP209 PMU IC 4GB NAND FLASH memory available only on the 4GB version of the board Android already loaded on the NAND available only on the 4GB version of the board MicroSD card UART console Status LEDs RESET RECOVERY buttons e 6 connectors x 40 pin each x 0 05 step PCB dimensions 3200x2200 mil 81x56 mm Page 6 of 41 OLIMEXO 2015 A20 SOM user s manual 1 4 Board variants There are two major board variants named A20 SOM and A20 SOM 4GB The 4GB version has built in NAND memory that allows the storage of an operating system without the need of a SD card at the moment of writing this document Olimex provides only Android OS for the NAND The 4GB version comes with already programmed and ready to use Android OS image The other Olimex board with close characteristics is A13 SOM board It is much cheaper and smaller It heats less and consumes l
16. al computer check the USB cable 4 The board might enter sleep mode very fast especially if the Android was turned off without the Quick Boot mode being ticked on Try pressing or holding down the PWR button for a couple of seconds to wake it up Q How do I write the Linux image to a micro SD card to use with my A20 board A First visit the wiki article for the board and download the archive with the image Then write the Linux image to a microSD card Under Windows we use Win32 Disk Imager http sourceforge net projects win32diskimager Download Win32 Disk Imager software Insert card Start program Select file Click write To write a Linux image to an SD card under Linux For instance an image with the file name of debian 2g img would be downloaded to a microSD 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 The tips above can also be used to prepare a microSD card with an Android image suitable for a microSD card Page 37 of 41 OLIMEXO 2015 A20 SOM user s manual Q How to edit board configurations and definitions in the official Debian Linux A Do you want a custom video resolution output Do you need a different port definition Do you need to change the hardware definitions of the board It is explained above in the manual But you can also visit this wiki article wik
17. board designs are fully open source but harder to implement in own solutions and require more of a hardware experience to do so Nevertheless OLinuXino boards are pretty good choice for evaluating the capabilities of the embedded processors Page 5 of 41 OLIMEXO 2015 A20 SOM user s manual 1 2 Target market of the board Using the A20 SOM as a stand alone development board would be more suitable for users with some hardware experience or people already familiar with other single board Linux boards and designs As mentioned in the previous chapter the board is meant to be implemented in a hardware design In which cases a stand alone A20 SOM without A20 SOM EVB board might not be suitable for you 1 If you are a beginner with single board Linux computers 2 If you are an OSHW purist 3 If you are looking for more straight forward software development and you are not going to implement the A20 SOM in own hardware products In the cases above it might be a better idea to take a look at the OLinuXino boards like A20 OLinuXino MICRO It is highly recommended to use A20 SOM with A20 SOM EVB initially unless you have previous experience with SOM or OLinuXino boards manufactured by OLIMEX A20 SOM might be is used altogether with A20 SOM EVB In that case the board s target market widens drastically the combination is suitable for embedded programming enthusiasts Linux and Android gadget fans they can just use the board as a medi
18. cases in which you prove power supply to both 5V and 5VEXT power lines 6 8 Additional hardware components The components below are mounted on the A20 SOM but are not discussed above They are listed here for completeness Reset button used to reset the board Power button used to power up the board Recovery button used to wake up the board from power down state 1GB 2x 4Gb 256 M x 16 bit DDR3 SDRAM the exact memory used currently is SAMSUNG K4B4G1646D BCKO the memory clock in board revisions A and B of A20 SOM was 384MHz the memory clock in hardware revisions C D and newer ones is improved to 480MHz The DDR3 memory part name in the schematic might be outdated We have used a number of different but fully compatible DDR3 memories due to supply unavailability It is always recommended to check the exact memory name printed on the component itself 4GB 1x 32Gb 4096 M x 8 bit NAND FLASH only available on the 4GB version of the board the exact memory used in the board revision mentioned is HYNIX H27UBG8T2A PWR LED turns on upon powering the board CHGLED lights when charging a battery connected to the Li Po battery connector Page 31 of 41 OLIMEXO 2015 A20 SOM user s manual CHAPTER 7 SCHEMATICS 7 Introduction to the chapter In this chapter is located information about the schematics describing logically and physically A20 SOM 7 1 Eagle schematic A20 SOM schematics may be found it on
19. e at the GPIO connectors that might be used as input is the one named 5VEXT The rest of the power signals are outputs and it would be incorrect to try to power the board from there 6 5 1 GPIO 1 General Purpose Input Output 40pin connector GPIO 1 connector Pin Signal name 5V 3 0VA a 3 Seu oTG pp 7 Processor pin Pin POWER CIRCUIT POWER CIRCUIT POWER CIRCUIT 12 5 5 ND O 7 usBe pRv 16 MICROPHONE 18 MIC10UTP 1 9 usBe vBUsbET ii usBe IDDET 13 usbi bRV i5 usB2 bRV i7 ubre ie ubve 2zi ubPi 3 25 uDP2 27 27 UDM2 n ul 2 U 37 P110 39 P111 i aiaiairircizxizx rr eieoej ei is izisimai u HIHIO Pl Plou pGlSioio ziziz 1 1 cilzizioiloiu aima mim o miciAajesie jonjoj zio ul UJ PION Cc Z zZ engl Ke C lt e a Gq Oo KE UU H HB D Page 25 of 41 OLIMEXO 2015 A20 SOM user s manual 6 5 2 GPIO 2 General Purpose Input Output 40pin connector ane m o m es 9 10 HTX1P 23 22 SEI 2 11SATA RXP 22 23 22 23 7 8 7 7 11 14 12 13 13 BA bom EC Emp PA 21UARTO TX ERXDO xj ase xj moo zo T T U U P R R P A D D SE ajwe 20 T 21 T 20 U 21 U 23 23 22 22 W 7 B E6 E E5 E 5 D 10 E E12 D E9 E E10 D mijo miuimimimi mi inmicIirir cz Irjeojoju vi ciai iaiaiaialiais id aliad He r xix elixixixixi
20. e 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 the requirement various depending on whether you use the board stand alone or on top of A20 SOM EVB 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 PWR button to start it you can change to fast boot when you
21. ed at the wiki article of the device https www olimex com wiki A20 SOM 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 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 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 Page 17 of 41 OLIMEXO 2015 A20 SOM user s manual CHAPTER 3 BOARD DESCRIPTION 3 Introduction to the chapter Here you get acquainted with the
22. em On a Module OLIMEX System on Module SOM boards are powerful Linux capable boards They follow a low cost modular design which allows rapid product development Each of these boards has two parts a main part which nests the processor the memory and the power control unit and the peripheral part which contains the USB ports the video output and most of the connectors SOM designs are targeted at customers who want to apply custom modifications and own solutions based on a specific processor without having to deal with multi layer PCBs with controlled impedance and BGA assembly This makes it possible to create simple boards that might be manufactured by your local board manufacturer containing only the peripherals you need with the dimensions and shape suitable for your specific solution Both the main part and the peripheral part of the SOM system have support in the official Android and Debian images distributed by Olimex and maintained by Olimex and the Linux community These images are typically available at the wiki articles of the boards The peripheral part of the SOM design is considered Open Source HardWare OSHW and the customer has access to the board source files that we used to manufacture it The part of the design that has the main microcontroller is considered proprietary design and design files would not be shared If you are looking for open source design of the processors used please check the OLinuXino boards OLinuXino
23. en 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 Furthermore if the board has entered power down state you can bring it back without restart using either the RECOVERY or the PWR_BUT 2 3 2 Mounted powering Typically A20 SOM gets evaluated when mounted on A20 SOM EVB In this case the former is powered via the latter The power line altogether with a number of other important processor lines is transferred via the 40 pin headers A20 SOM receives power from A20 SOM EVB but what are the requirements to power A20 SOM EVB You need to provide 6V to 16V DC voltage to the power jack named PWR of A20 SOM EVB board The DC barrel jack has 2 0mm inner pin and 6 3mm hole More information about the exact component might be found here https www olimex com wiki PWRJACK Do not provide AC voltage to the A20 SOM EVB board Do not provide more than 16V of voltage to the A20 SOM EVB board The typical consumption of A20 SOM EVB A20 SOM is between 150mA 2 12V and 250mA 12V depending on the processor s current load For the European customers we also stock and sell basic power supply adapters compatible with the power jack The default username password combination for the default Linux image on the SD card if purc
24. er capacities of the microSD cards compared to SD or MMC cards It is suggested to have an SD card with a proper Linux Android image especially if you have ordered a version of the board without NAND memory It is SD MMC Bea CL 470nH 0805 0 3R 250mA C91 22444284 CMD DI 2 3 6 recommended to use Class 10 LOMByte sec card p GIE 4 USS for faster read write operations since lower class SDO CLK 5 cLK SCLK j 4 87182 SDO DO 7 DaTO DO cards especially higher capacity ones might slow 4 318182 SR 8 Gert ge down the whole system T RA1206 4X0603 4B8 100k 2 D ac CRL G3 SDO DET j j i Le TFC HPAPR 08 You can also find the table with the pinout of the 10k microSD connector on the next page L J Page 23 of 41 OLIMEXO 2015 A20 SOM user s manual SD MMC connector perc connector o BCEE ges dme apauys esr que sam vererem eer es 6 4 Power pins for external power supply The recommended way of powering the board are the power pins located on the UARTO connector They are suitable for 5V DC external power supply unit The required current may vary depending on the peripherals connected to the board The power supply should be capable of providing at least 0 5A of current The UARTO connector features also the pins suitable for serial communication with the board For t
25. er s manual m AUDIO W Integrated HI FI 100dB Audio Codec m Dual analog mic amplifiers More information can be found on Allwinner s web site at the following web address http www allwinnertech com en clg processora A20 html 4 2 Block diagram The block diagram is taken from Allwinner s web site ARM Cortex A7 Thumb 2 FPU User Interface GPU Memory Keypad RTP ARM Mali400 DDR3 DDR3L DDR2 IR LRADC ARM Mali400 NAND Flash Connectivity System Display Interface USB OTG 2 USB HOST interrupt Controller GMAC EMAC SD MMC Timer HS Timer 2 m TV Encoder 8 UART PCM I2S AC97 TV Decoder Page 20 of 41 OLIMEXO 2015 A20 SOM user s manual CHAPTER 5 CONTROL CIRCUITY 5 Introduction to the chapter Here you can find information about reset circuit and quartz crystals locations the power supply circuit is also briefly discussed 5 1 Reset The board has hardware reset controlled by the AXP209 power system management IC It is a good practice to perform software reset of the board Performing reset by disconnecting the power supply might lead to software corruption of the operating system of choice 5 2 Clocks 32 768 Hz RTC quartz crystal Q1 is found at pins F1 and F2 of the A20 microcontroller 24 MHz quartz crystal Q2 is found at pins N22 and N23 of the A20 microcontroller 5 3 Power supply circuit The power supply is handled mainly by AXP209 power management system an Allwinner chip that goes together with the A20 proce
26. es whether you are using Android or Debian 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 A20 board here https www olimex com wiki A20 SOM 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 not dependent on the current video output resolution a cable like USB SERIAL CABLE F When the board boots type change_display or Jchange display a20 SOM sh It looks like this Page 12 of 41 OLIMEXO 2015 COM 13 PuTTY A20 SOM user s manual Then the main menu of the video configuration script shows up Select output type ET Disable all screens LCD Set configuration for LCD HDMI Set configuration for HDMI VGA Set configuration for VGA dE Choose the resolution and the interface LCD HDMI or VGA The supported resolutions are listed on the next page For LCD 1 4 3 480x272 2 7 800x480 3 10 1024x600
27. ess power However it features a generation older processor and lesser amount of RAM memory making it less desirable for heavy computations for instance high resolution video decoding and encoding Other SOM boards that might be compared to functionality are the and quad core ARM Cortex A9 RK3188 SOM and the BeagleBone inspired AM3352 SOM 1 5 Board versions used in the manual The documents follows the hardware layout of A20 SOM board revision D There might be revision B pictures left over Note that major changes in the hardware design were introduced in A20 SOM board revision C Boards from the initial couple of revisions have visible differences compared to boards from revisions C and on Yet the two major functional differences are the improved memory clock speed 480MHz compared to the initial 384MHz and the presence of the additional GPIO 6 connector It is important to notice that different board revision might use different Debian images A20 SOM EVB revision C peripheral board was used while writing this document Different board revisions might have different features or settings It is possible that parts of this document do not apply to all board revisions 1 6 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 2 provides a guide for quickly setting up the board and software notes Chapter 3 contain
28. ftware 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
29. hased 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 the voltage regulators and the main processor 2 4 Button functions The three buttons listed bellow 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 5 seconds to perform each action RECOVERY used to wake up the board from sleep RESET used for hardware reset of the board before using it please refer to the note below 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 your board has NAND memory you can corrupt the image located on the NAND memory Page 10 of 41 OLIMEXO 2015 A20 SOM user s manual 2 5 Interacting with the board The typical and recommended way of interacting with A20 SOM board is via a serial cable connected between the UART DEBUG header and a personal computer You would probably need a cable suitable for such a connection due to the fact that most personal computers lack a
30. he powering we are only interested in pins 5VEXT and the pin next to it GND The signal names are printed under the pins make sure to inspect the names before connecting the supply More info about the power supply can be found in chapter 5 of this manual 6 5 GPIO connectors There are 6 GPIO connectors located on the top side of A20 SOM They ease the access to processors pins These connectors except for GPIO 6 also provide a way to mount the board to a board with peripherals Important boards revisions prior to revision C have only 5 x GPIO connectors The 14 pin GPIO 6 connector is not available Below you would find tables with the signal at each pin To understand better what each processor pin does it might be a good idea to refer to the datasheet of the A20 processor The schematic of the board of peripherals A20 SOM EVB might also help you identify the main function of the pins To keep the form factor as small as possible the GPIO connectors have 0 05 step IMPORTANT the connectors are very fragile if you attempt to disconnect the board by pulling only one side out it might break Furthermore you might bend the board s pins Use pliers or other suitable object to disconnect the connectors carefully Page 24 of 41 OLIMEXO 2015 A20 SOM user s manual OLIMEX sells additional and replacement male and female 0 05 50 mil step connectors We also have a suitable cable named CABLE 40 40 10CM The only power lin
31. i article Q How to edit board configurations and definitions in the official Android images A There is a wiki article about that please visit wiki article Q Is it possible to boot Debian from NAND Do you provide such image A It is possible bu we don t provide such image There are people who were successful in booting Debian from the NAND however Make sure to check on the forum Q How to generate boot able SD card Debian Linux image for A20 SOM Build instructions and required files for the latest Debian images GitHub location Note that Linux Sunxi Kernel is a work in progress this means you can try the current stage sunxi x x branch but if something is broken and doesn t work just revert to the git tags we give in the blog and they would work for sure Sunxi u boot loader the linux sunxi git page contains a lot of sources for all Olimex Allwinner boards Q How to detect and enable the Ethernet controller if it is disabled by default A 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 ethO name then write dhclient ethO This should enable the Ethernet and then SSH would also be available You can also enable auto detection of Ethernet on power up by removing the comment auto ethO in etc network interfaces in the Linux image Q How to download the prebuilt Android image to a microSD card A First downl
32. ipping box Please note It is your responsibility to ensure that returned goods reach us Please use a reliable form of shipping If we do not receive your package we will not be held liable Shipping and handling charges are not refundable We are not responsible for any shipping charges of merchandise being returned to us or returning working items to you The full text might be found at https www olimex com wiki GTC Warranty for future reference Page 41 of 41
33. ivers from the respective executable or manually point the installer to the drivers folder in the PhoenixSuit installation path 8 PhoenixSuit will detect the board and would ask whether you wish to also of writing the image Choose method of writing the image and confirm your wish to write the image 9 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 Page 40 of 41 OLIMEXO 2015 A20 SOM user s manual 8 5 Product support For product support hardware information and error reports mail to support olimex com All document or hardware feedback is welcome Note that we are primarily a hardware company and our software support is limited Please consider reading the paragraph below about the warranty of Olimex products All goods are checked before they are sent out In the unlikely event that goods are faulty they must be returned to OLIMEX at the address listed on your order invoice OLIMEX will not accept goods that have clearly been used more than the amount needed to evaluate their functionality If the goods are found to be in working condition and the lack of functionality is a result of lack of knowledge on the customers part no refund will be made but the goods will be returned to the user at their expense All
34. located in the main partition of a prepared microSD card 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 lt gt 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 Page 14 of 41 OLIMEXO 2015 A20 SOM user s manual The typical A20 SOM user would not need to edit the files however 2 8 Connecting and calibrating a display One of the ways to interact with the board is via an external display with or without touchscreen component However there is only a 40 pin female connector LCD_CON with a 0 05 step Unlike other OLIMEX Allwinner boards the A20 SOM lacks a row of pins that allows the user to connect a display out of the box The board s LCD_CON connector is female and has a smaller 0 05 step This means that if you use a display made by OLIMEX you would need additional 2x20 MALE MALE 0 05 header to convert the female connector to male The 0 05 headers are somehow hard to find so we sell them here 0 05 step connec
35. n about the heart of A20 SOM its microcontroller The information is a modified version of the datasheet provided by its manufacturers 4 1 The processor The main feature of the A20 processor is the sheer computing power that allows FullHD video playback The graphical processing unit is also pretty powerful and supported by the default software packages that come with the SOM boards The software support for the features in the processor is at pretty good state thanks to the efforts of the community and Allwinner themselves The full list of features might be found below BH CPU BH ARM Cortex A7 Dual Core m GPU B ARM Mali400MP2 W Complies with OpenGL ES 2 0 1 1 m VIDEO m HD H 264 2160p video decoding W Multi format FHD video decoding including Mpeg1 2 Mpeg4 SP ASP GMC H 263 H 264 VP6 8 AVS jizun Jpeg Mjpeg etc H 264 High Profile 1080p 230fps or 720p 60fps encoding 3840x1080 30fps 3D decoding BD SBS TAB FP supported Complies with RTSP HTTP HLS RTMP MMS streaming media protocols m DISPLAY Supports multi channel HD display Integrated HDMI 1 4 transmitter with HDCP support CPU RGB LVDS LCD interface Supports CVBS Y PbPr VGA Integrated TV decoder BH CAMERA Integrated parallel 8 bit I F YUV sensor Integrated 24 bit parallel YUV 444 I F Supports 5M CMOS sensor Supports dual sensors BH MEMORY m DDR2 DDR3 DDR3L controller B NAND Flash controller with 64 bit ECC Page 19 of 41 OLIMEXO 2015 A20 SOM us
36. need it to use one of the images available If you decide to use Debian you would also need a card Official Android and Debian images are available at the wiki article for the board Recommended items A20 SOM EVB reference design of a 2 layer board for A20 SOM which adds VGA HDMI Audio in out LCD 2 MP camera Gigabit Ethernet SATA USB OTG and 2 USB hosts The A20 SOM EVB board also adapts the 0 05 step GPIO headers to 0 1 step headers so you can easily attach an LCD or UEXT module Its hardware design is open source and available as Eagle CAD files so everyone can modify and tailor it according to the specific needs Some of the above suggested items can be purchased by Olimex for instance USB SERIAL CABLE F female USB serial console cable provides the easiest way of debugging A20 SOM REV D DEBIAN SD a tested class 10 micro SD card suitable for A20 SOM boards revision C or newer with latest by the time of leaving the Olimex facilities official Debian release A20 SOM DEBIAN SD a tested class 10 micro SD card suitable for A20 SOM boards revision A and revision B with latest by the time of leaving the Olimex facilities official Debian release A20 SOM ANDROID SD a tested class 10 micro SD card with the latest by the time of leaving Olimex facilities official Android release 2 3 Powering the board The powering requirements of the A20 SOM are different depending on whether you use it in stand alone mode or
37. oad one of the official Android images which might be found in the Android section above Make sure that the download link you visit clearly indicates that the image is suitable for the microSD card since there are images suitable for NAND memory also The images suitable for the microSD memory and those suitable for NAND card are different However the upload method is almost identical using PhoenixSuit There are two types of Android images for microSD card that we usually provide and each of them has to be downloaded to a microSD card using a different method The image provided for microSD card is either the native Android image that can be downloaded to the card via a software tool like Page 38 of 41 OLIMEXO 2015 A20 SOM user s manual PhoenixSuit through the board or an image taken from an already prepared microSD card that requires to simply write the image through a microSD card reader It is more likely that you have an Android image that requires a simple copy to a card If that is the case you can follow the exact steps as for Linux e g using Win32 Disk Imager or dd command In order to prepare a microSD card with a native Android you will need a software tool called PhoenixSuit and then Install and run PhoenixSuit Go to the firmware tab of the program and point to a valid Android image note that the images on Google drive are compressed and you have to extract the archives to img files to be able writ
38. ows you to connect to a personal computer with a free USB port If you decide to make your own cable you would need to consider that the levels at board s UARTO 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 It is highly recommended to have an USB SERIAL CABLE F or similar product at hand when debugging the video output is not always reliable and if you set wrong display settings you might be unable to recover the settings without a proper UARTO connection For more information please refer to chapter 2 5 Interacting with the board 6 2 UARTO pins The UARTO interface might be used for serial communication between the board and a personal computer by default In the case of a video output problem a cable might provide the needed feedback and greatly reduce the efforts needed to repair the board or to adjust the software setting Note that by default only UARTO is defined as a port suitable for serial debug You can use our USB SERIAL CABLE F for debugging Even when A20 SOM is mounted on A20 SOM EVB the default debug port remains UARTO despite that it gets additional pins on the big board also for easier access UARTO ep POWER CIRCUIT 4 aND POWER CIRCUIT 5 5VEXT POWER CIRCUIT Page 22 of 41 OLIMEXO 2015 A20 SOM user s manual Consider the table on the previous page when connecting the USB SERIAL CA
39. returns must be authorized by an RMA Number Email support olimex com for authorization number before shipping back any merchandise Please include your name phone number and order number in your email request Returns for any unaffected development board programmer tools and cables permitted within 7 days from the date of receipt of merchandise After such time all sales are considered final Returns of incorrect ordered items are allowed subject to a 10 restocking fee What is unaffected If you hooked it to power you affected it To be clear this includes items that have been soldered to or have had their firmware changed Because of the nature of the products we deal with prototyping electronic tools we cannot allow returns of items that have been programmed powered up or otherwise changed post shipment from our warehouse All returned merchandise must be in its original mint and clean condition Returns on damaged scratched programmed burnt or otherwise played with merchandise will not be accepted All returns must include all the factory accessories which come with the item This includes any In Circuit Serial Programming cables anti static packing boxes etc With your return enclose your PO Also include a brief letter of explanation of why the merchandise is being returned and state your request for either a refund or an exchange Include the authorization number on this letter and on the outside of the sh
40. s Erde CHAPTER 7 SCHEMATICS EE hu J2 7 Introduction to the chapter SET ERE SE EE RA EE TERM Se T UNIS PA CHAPTER 8 REVISION HISTORY AND SUPPORT eee JS 8 Introduction to the Chapter sssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssccsscsssess 33 Page 4 of 41 OLIMEXO 2015 A20 SOM user s manual CHAPTER 1 OVERVIEW 1 Introduction to the chapter Thank you for choosing this single board computer from Olimex This document provides a user s guide for the A20 SOM 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 A20 SOM development board enables code development of applications running on the A20 microcontroller manufactured by Allwinner Technology from China The A20 SOM is typically used together with A20 SOM EVB which features most of the peripherals and connectors needed for full evaluation and utilization of the A20 processor The hardware design of A20 SOM development board is considered intellectual property to Olimex The hardware design files are considered copyright material and would not be distributed A20 SOM EVB board is an open source open hardware project and all documentation is available to the customer The software support for both boards is open source and released under GPL license 1 1 Introduction to SOM Syst
41. s the general board diagram and layout Chapter 4 describes the component that is the heart of the board the A20 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 Page 7 of 41 OLIMEX 2015 A20 SOM user s manual CHAPTER 2 SETTING UP THE A20 SOM BOARD 2 Introduction to the chapter This section helps you set up the SOM 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 warnings A20 SOM boards are 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 If this is not possible please use isolators like USB ISO to save your development board from potential over voltage If you connect
42. serial port nowadays Even if you have serial port you should respect the CMOS levels of the board which are incompatible with the TTL levels of your computer We distribute a ready to use plug and play cable it is called USB SERIAL CABLE F 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 https www olimex com Products Components Cables USB Serial Cable USB Serial Cable F You need to connect the serial cable lines as follows RX line to UARTO TX pin TX line to UARTO RX pin GND to GND Make sure that the serial cable is connected to your personal computer and recognized properly after driver installation After the hardware connection is established open a terminal program on the serial COM port which the cable is associated with The typical baud rate is 115200 the rest of the settings should be left as per default After everything else is set you would need to power the board as explained in 2 3 Powering the board In the command line interface of the official Debian images you are automatically logged as root The default superuser username password combination in the GUI LXDE of the official images is olimex olimex If the A20 SOM is attached to A20 SOM EVB 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 2 a monitor via the
43. ssor It is mounted on the board but since it is relatively hard to find we also sell it separately if you have provided over voltage and want to repair the board yourself A20 SOM typically consumes between 0 20A and 0 25A when connected to a 5V voltage source provided at pins GND and 5VEXT During heavy load of the processor the consumption might raise up to 0 35A tested with top dO The current consumed might have peaks as high as 0 50A during start up when different modules are initialized Make sure your supply is capable of providing at least half an ampere of current at 5V of voltage For more info on how to power the board refer to chapter 2 3 Powering the board Page 21 of 41 OLIMEX 2015 A20 SOM user s manual CHAPTER 6 CONNECTORS AND PINOUT 6 Introduction to the chapter In this chapter are presented the connectors that can be found on the board all together with their pinout and notes about them Jumpers functions are described Notes and info on specific peripherals are presented Notes regarding the interfaces are given 6 1 Communication with A20 SOM in Linux The direct access method to the Linux command interface is via the serial interface You would need to use the pins of the UARTO and then use your favorite terminal program puTTy minicom picocom teraterm etc to access the command line interface of the debian the data send commands You can use USB SERIAL CABLE F with the UARTO interface that all
44. st 7 LCD display with optional touchscreen component 800x480 LCD OLINUXINO 10TS low cost 10 LCD display with optional touchscreen component 1024x600 LCD OLINUXINO 15 6 low cost 15 6 LCD display 1366x768 LCD OLINUXINO 15 6FHD low cost Full HD 15 6 LCD display 1920x1080 ALUMINIUM HEATSINK 20x20x6MM heatsink radiator for better processor heat dissipation Page 35 of 41 OLIMEXO 2015 A20 SOM user s manual How to purchase You can purchase directly from our online shop or from any of our distributors Note that usually it might be faster and cheaper to purchase Olimex products from our distributors List of confirmed Olimex LTD distributors and resellers https www olimex com Distributors Please visit https www olimex com for more info Page 36 of 41 OLIMEXO 2015 A20 SOM user s manual 8 4 Frequently asked questions Q I powered my board it showed a logo and then nothing happened What might be the problem A This might be due to a number of reasons but it is recommended to try the following 1 Download latest official image from our wiki either Android or Debian for SD card and upload it to an SD card again There are instructions how to do it in the other questions below Try if the board works now 2 Check if your power supply provides enough current try with different better power supply 3 Check the USB hub you are using plug the USB cable directly to the back of your person
45. the CMOS TTL convertor Added information about SSH connection Re via miniUSB connector and VGA video Updated FAQ Updated electrical polarity warning Updated DDR3 memory according to the latest schematic Multiple minor errors were fixed EE Multiple stylistic mistakes were fixed Bi Rhy tle deg 23 H 17 03 2015 8 30 36 37 38 Page 33 of 41 OLIMEXO 2015 A20 SOM user s manual 8 2 Board revision Remember to check the schematics and the board design files to compare the differences A initial release of the board 1 Optimized values 2 Resolved various multiplexing issues 3 Renamed few wires properly 1 Major routing and layout differences with previous hardware revisions General hardware improvement of the board based on A20 OLinuXino Lime2_Rev_B s memory routing General layout improvement Additional GPIO connector 2 Added GPIO 6 connector with the following signals FMINL FMINR TVIN2 TVIN3 VMIC_OUT AXP_BACKUP AXP_RST AXP_PWRON UBOOT_SEL VDD_RTC and GND 3 Various value optimizations 4 Memory clock now upped to 48 Mhz from 384Mhz 1 Added VGA resistor matrix 2 Minor hardware optimizations adjustments Page 34 of 41 OLIMEXO 2015 A20 SOM user s manual 8 3 Useful web links and purchase codes The web pages you can visit for more information about A20 SOM are https www olimex com Products SOM A20 A20 SOM and https www olimex com Products SOM A20 A20 SOM 4GB A20 S
46. tors Newer displays made by Olimex have both 0 1 and 0 05 step connectors Going for an LCD output you would also need need a compatible cable to attach the display to the board The cable is sold separately The displays recommended for the board at the moment of writing might be found in the table below Display name Size of Native Official Official Link to product display resolution Debian image Android image page in inches in pixels support support LCD OlinuXino 4 3TS 4 3 480x272 Yes No Product page LCD OLinuXino 7 7 800x480 Yes Yes Product page LCD OLinuXino 7TS 7 800x480 Yes Yes Product page LCD OLinuXino 10 10 1 1024x600 Yes Yes Product page LCD OLinuXino 10TS 10 1 1024x600 Yes Yes Product page LCD OLinuXino 15 6 15 6 1366x768 Yes No Product page LCD OlinuXino 15 6FHD 15 6 1920x1080 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
47. 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 SOM A20 SOM 4GB AND A20 SOM EVB THEY ARE CONSIDERED SUITABLE ONLY FOR A20 SOM A20 SOM 4GB AND A20 SOM EVB RESPECTIVELY Page 2 of 41 OLIMEXO 2015 A20 SOM user s manual Table of Contents VTS CTA IVER LE 2 CHAPTER 1 OVERVIEW EE 5 1 Introduction to the chaptet ege ue 5 2 3 2 Mounted POW ENING RTT RTERRTCERETERREEERERERCIOTERETRTEEENS 10 2 8 Button funcions os oss ecd oi SR E i p pd eod ub bU HE cH cit REFS H EU e eU REFERO IN DEAD RU HPE Cod 10 2 6 1 Android caliDratiOn oceano oo ooa in eo seo to ep Y anas e nao n ana dn ao EEN siero visieou ei ngay daresi 16 SAVOIR E TEE 16 CHAPTER 6 CONNECTORS AND PINOU T ccccsssssscccsscsscsscsssocsscsssseees 22 6 Introduction to the Chapte scsscccsscsssssssssssscssssscssssssnssscccssccsssssncessccsssssesssssnsesssssesssess 22 6 1 Communication with A20 SOM in Lintix sssssssssssssssssssssssssssssssssssssssssssssssssssssssseees 22 Page 3 of 41 OLIMEXO 2015 A20 SOM user s manual 6 2 UARTO RUD ttt 22 6 3 MicroSD card CONMECTOL 00sssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssscssscsscssssesss
48. x msix xx i x o lo 5 mjioJj OoJ SoISo a3lo SIS 3 NLA ZIWIN PI elol2 z D Alu ka Uu Ke 4 x 3 D 3 m d Page 26 of 41 OLIMEXO 2015 A20 SOM user s manual 6 5 3 GPIO 3 General Purpose Input Output 40pin connector Pin Signal name Processor pin abs POWER CIRCUIT ND E POWER CIRCUIT ND 5 PH SDC3 DET 6 3 4 7 PH2 LED 4 9 PH8 10 PB5 UJ eu E Ke TU TU vivlolo iu T ow wo K N HB HB oa M B N 3 ai H 3 ET 3 D B UJ UJ w 1 PH9 12 PB6 1 i3 PH10 14 PB7 elen 16 PB8 17 PH12 CSI STY 1 18 PB10 19 PH13 CSI RST 1 2e PB11 n PH20 PH21 PH22 PH23 RIN 24 PB13 lt 28 PB15 30 PB16 32 PB17 34 PH24 36 PH25 38 PH26 NI RPITN Nje v v T I ur HB Ei wu ps Page 27 of 41 OLIMEXO 2015 A20 SOM user s manual 6 5 4 GPIO 4 General Purpose Input Output 40pin connector Pin Signal name Processor pin Pin Signal name 1 5vExT POWER CIRCUIT N als 3V POWER CIRCUIT 5 PEO CSIO PCLK E23 5 PE1 CSIO MCLK E22 PE7 CSIO D3 22 10 PE2 CSIO HSYNC D23 11 PES CSIO DA 23 12 PE3 CSIO VSYNC D22 13 PE9 CSIO D5 A22 14 PEA CSIO DO C23 15 PE10 CSIO D6 B21 16 PE5 CSIO DI C22 17 PE11 CSIO D7 A21 18 PE6 CSIO D2 B23 19 UART7 TX 20 UART7 RX E13 21 PB18 TWI1 SCK PB19 TWI1 SDA B8 28 UART6 RX D16 3e TWI2 SDA 32 sP12 MOSI 34 sP12 Cse 3e P115 38 NMI N Iw z Lo E IO m UU is 4 H o m HG UJ 1 l l C N 2 Lo H G CO lt 7 TWI SD
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