Power & Source of Big Ideas

Hello All, I try to access GPIO of NanoPC T4 and use libfriendlyarm-things.so Library for android. -Down load source code https://gitlab.com/friendlyelec/rk3399-android-8.1/tree/master/vendor/friendlyelec/apps/GPIO_LED_Demo -Following instruction in http://wiki.friendlyarm.com/wiki/index.php/Friendl...
It works. I can open I2C port.
nanopc-t4:/ # chmod 0666 /dev/i2c-0
nanopc-t4:/ # chown system system /dev/i2c-0
11-19 02:52:42.566 2452 2452 I: Open i2c device node files/address.txt
11-19 02:52:42.567 2452 2452 E: i2c_fd : 63
Thank you. I will try it. This way I donot have to rebuild and flash the NanoPC.
When runing I2C_LCD1602_Demo, It canot open I2C port and show error message
Fail to open I2C device
Here is the code https://github.com/friendlyarm/friendly ... D1602_Demo
What can be the error? Do I have to setup hardware or connection for I2C to run the demo?
Hello v8dave,

Can you send a link where I can get source code of I2C driver? I could list all 6 I2C ports, but I can not open any of them.

i2c_fd = open("/dev/i2c-3", O_RDWR);

The function open() return i2c_fd = -1
Do you know why.
Thank you
Hello v8dave, There is a problem I write the JNI code. But can not open the serial port / UART. When call following function fd_ = ::open (port_.c_str(), O_RDWR | O_NOCTTY | O_NONBLOCK); It always returns -1 Do you have any suggestion? Here is the snap code: =================== SerialImpl::SerialImp...
Hello v8dave,
Thank you. That is good. I can use JNI for communication.
Hello, Are there any Android Studio project using libfriendlyarm-hardware.so library? Using NanoPC-T4 and build the SerialPortDemo with libfriendlyarm-hardware.so. The steps: -Create Android Studio project -Add the library libfriendlyarm-hardware.so under /src/main/jniLibs/armeabi -Add build.gradle:...
Hello, Working with NanoPC-T4 and build the SerialPortDemo with libfriendlyarm-hardware.so in Android Studio. The steps: -Create Android Studio project -Add the library libfriendlyarm-hardware.so under /src/main/jniLibs/armeabi -Add build.gradle: android{ ... sourceSets.main { jniLibs.srcDir 'src/ma...