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===GPIO under Linux===
===GPIO under Linux===
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== How To? ==
== How To? ==
- A13 Cortex-A8 CPU and Mali 400 GPU
- 256 or 512MB DDR3 RAM memory
- Power supply managment
- 1x LCD connector
- 3x GPIO connectors
- MicroSD card connector
- DEBUG-UART connector for console debug with USB-SERIAL-CABLE-F
- status LED
- Power LED
- RESET button
- 3.3V input power supply
- PCB dimensions: 61 x 33 mm
Official Images from OLIMEX
Torrent of Debian release 1: A13-SOM-256 Debian Linux with kernel 3.4.90+
Direct download location of Debian release 1: A13-SOM-256 Debian 4GB SD-card image release-1 with hardware accelerated video and more
Torrent of Debian release 1: A13-SOM-512 Debian Linux with kernel 3.4.90+
Direct download location of debian release 1: A13-SOM-512 Debian 4GB SD-card image release-1 with hardware accelerated video and more
The image features:
- Linux Kernel 3.4.90+
- XFCE4 desktop environment
- Mplayer CLI
- GCC 4.6
- 4.3"(480x272), 7"(800x480), 10" (1024x600) and 15.6" (1366x768) LCD and touchscreen support
- USB WIFI RTL8188CU, Ethernet AX88772B
- Python 2.7
- A13-LCD 4.3″TS 4.3″ LCD with backlight and touchscreen 480×272 pixels
- A13-LCD7″TS 7″ LCD with backlight and touchscreen 800×480 pixels
- A10-LCD10″TS 10.1″ LCD with backlight and touchscreen 1024×600 pixels
- Micro SD card
- OTG USB
- HIGH SPEED HOST1 USB
- Default Login: root/olimex
Tested board peripherals with this image:
- GPIO - located at /sys/class/gpio
- LCD - supported are A13-LCD4.3TS, A13-LCD7TS, A13-LCD10TS
- Touch screen - you need calibrate LCD before using touch screen. Type: ts_calibrate and then test it with ts_test
- ASIX 8877 USB-LAN - USB-ETHERNET-AX88772B
- RTL8188CU - MOD-WIFI-RTL8188
- USB_OTG - works as OTG device and Low/Full/High USB host
- USB_HOST - works as Low/Full/High USB host
- mico_SD_card - allow Linux boot
- I2C2(100KHz) - /dev/i2c-2
- I2C1(100KHz) - /dev/i2c-1
Note: the A13-SOM-Debian-SD card which we have in our web store contains the same image on 4GB Class10 fast micro SDcard, if you want to use this image please use card of Class10 speed or the performance of Linux will be very slow.
Note: in the previous Debian releases the Ethernet was auto-detected and initialized during boot BUT this was causing big delays in the start-up of the board if you didn't want to use Ethernet or if there wasn't Ethernet cable connected.
You can enable it by following these two steps:
1. To check under what name the LAN is associated write "ifconfig –a"
2. If, for example, it is under eth0 name, then write: "dhclient eth0"
This should enable the Ethernet and then SSH would also be available.
Note that the Android is suitable only for the A13-SOM-512 version of the board (the 256 version of the board is not equipped with enough RAM to run Android smoothly). To upload the Android to the NAND you would also need A13-SOM-WIFI-4GB (to extend the board with NAND flash memory).
Torrent of Android 4.2.2 release 1 for NAND memory: A13-SOM-512 Android for NAND
Direct download of Android 4.2.2 release 1 NAND memory: A13-SOM-512 Android for NAND
The image is with these features:
- Android 4.2.2
- NAND image i.e. will work only on [A13-SOM-512+A13-SOM-WIFI-4GB]
- Supports 7" LCD 800x480 pixels
- Touchscreen supported
- GPIO support
- USB-Ethernet ASIX 88772
- USB-WIFI RTL8188
- USB-OTG support USB device and USB host with Low/Full/High speed
- USB-HOST-top Low/Full/High speed
- micro SD card
A13 User Manual
A13 Users manual
Power supply and consumption
A13-SOM can be powered from:
- +3.3V voltage applied to GPIO-1
Power consumption is as follows:
A13-SOM-XXX basic dimensions might be seen in the picture here: A13-SOM board dimensions
A13-SOM-256/512 schemaitc is available at GitHub
A13-SOM-WIFI schematic and CAD files are at GitHub
The CAD product used to design A13-SOM-WIFI is Eagle and you can download evaluation free version from their web.
Linux-Commands Brief Linux Command reference
The Debian Linux Python package for A13-SOM is called pyA13SOM. It is installed in the default Debian image. More information how it can be used might be found here:
GPIO under Linux
GPIO - they are located in /sys/class/gpio directory. Note that first you have to export GPIOs. For example: to add PB03
root@A13:~# echo 1 > /sys/class/gpio/export
to make PB03 output
root@A13:~# echo out > /sys/class/gpio/gpio1_pb3/direction
to make PB03 high level(3.3V)
root@A13:~# echo 1 > /sys/class/gpio/gpio1_pb3/value
to make PB03 low level(0V)
root@A13:~# echo 0 > /sys/class/gpio/gpio1_pb3/value
Full list with supported GPIOs is:
gpio12_pg9 gpio1_pb3 gpio4_pe4 gpio7_pe7
gpio10_pe10 gpio13_pg10 gpio2_pb4 gpio5_pe5 gpio8_pe8
gpio11_pe11 gpio14_pg11 gpio3_pb10 gpio6_pe6 gpio9_pe9
There might be multiplexing on some of the pins especially if you are using a shield! Consider that when picking a GPIO. Refer to the schematics of the board and the shield for clearer view of the possible multiplexing locations.
How to correctly power off OLinuXino running from NAND Flash
In this Blog post we explain what are the problems. This is common problem for all computers running OS. Here you can read more about MLC NAND Flash and Linux file system.
How to generate boot-able SD-card Debian Linux image for A13-SOM?
The building instructions might be found in this document: Google drive mirror
Official Wordpress post on Debian image release: Wordpress post
How do I write the Linux image to a micro SD card to use with my A13-SOM board?
To write a Linux image to an SD card under Windows we use Win32 Disk Imager):
- Download Win32 Disk Imager Win32 Disk Imager
- Insert card
- Start program
- Select file
- Click "write"
To write a Linux image to an SD card under Linux:
For instance you have an image with the file name of "debian_2g.img". It would be downloaded to the SD card connected to a Linux machine using one of the following commands:
- # dd bs=4M oflag=sync if=debian_2g.img of=/dev/sdX
- # cp debian_2g.img /dev/sdX
where X is the uSD card.
How to change HDMI, VGA and LCD resolutions?
The default SD card setup is made with settings for HDMI 720p/60Hz. If you want to change to some other LCD, VGA or HDMI resolution then you have to start change_display.sh script file in /root directory.
and press "Enter".
Then choose the resolution and the interface(LCD, HDMI or VGA). Note that the selection of a specific resolution is done by navigating with the arrow keys and pressing "space" button. Make sure the asterisk marks your selection properly.
The supported resolutions are:
- 1. 4.3" (480x272)
- 2. 7" (800x480)
- 3. 10" (1024x600)
- 4. 15.6" (1366x768)
Important: initially the boards are calibrated for a specific display. If you re-write the image (no matter whether the SD card or the NAND memory) you would need to use a mouse to calibrate the display initially. It might be impossible to calibrate it via touching the display.
- 0. 480i
- 1. 576i
- 2. 480p
- 3. 576p
- 4. 720p50
- 5. 720p60
- 6. 1080i50
- 7. 1080i60
- 8. 1080p24
- 9. 1080p50
- 10. 1080p60
For VGA: (note that the VGA signals are routed to custom 6 pin connector and you need from adapter to standard VGA connector)
- 0. 1680x1050
- 1. 1440x900
- 2. 1360x768
- 3. 1280x1024
- 4. 1024x768
- 5. 800x600
- 6. 640x480
- 7. 1920x1080
- 8. 1280x720
How to control PWM under Linux?
There is an article here: how to add pwm
How to edit board configurations and definitions in the official Debian Linux?
The biggest part of the board configuration might be edited, changed or improved in a file called script.bin
The script.bin file can usually be found in the main directory of a microSD card prepared with official Debian image. The folder containing the script can be inspected under both Windows, Linux or Mac.
You can't directly edit binary file so you would need to convert it to text format (it is called fex in this case), then edit the parameters via a text editor and finally switch it back to binary format.
The different options for the script are explained here: SUNXI 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
To convert back and fort the script.bin you might use different tools. You can find Windows tools here: SUNXI TOOLS FOR WINDOWS . For Linux convertors please check the sunxi tools here: SUNXI TOOLS
Note that it is possible to change the script.bin in a running Debian image in newest releases! More information might be found at the end of the document! Not all releases feature the live method of changing fex to bin so if you board doesn't have it follow the other methods.
Changing script.bin file without removing the microSD card:
The tools for script.bin changing are located in /opt/sunxi-tools directory
# cd /opt/sunxi-tools
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 and exit from nano editor
this will convert script.fex to script.bin and the script.bin file will be written to sdcard.
How to properly calibrate a display under Debian
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”).
enter the olimex password:olimex
calibrate the touch screen and reboot the board
It would be a good idea to test with Android or another Debian image also, it has a built-in calibration application by default.
How to add STK1160 video capture driver support in Kernel 3.4
STK1160 driver backport by Dimitar Tomov