# i2ctransfer -f -y 0 w9@0x50 0x64 val1 val2 val3 // Example // first: (bus0,write3 byte at offset 0x64 from EEPROM at 0x50) // andthen: (bus0, read3 byte at offset 0x64 from EEPROM at 0x50) # i2ctransfer -f -y 0 w9@0x50 0x64 val1 val2 val3 r3@0x50 # ...
printf("error during I2C_RDWR ioctl with error code %d\n", ret); } else if('r' == select) { printf("please input:address?(example:0x00)\n"); scanf("%x", ®_address); //从i2c里面读出数据 printf("began to read:"); work_queue.nmsgs = 1; //先设定一下地址 (work_queue.msg...
中调用...add函数: import ctypes plib = ctypes.CDLL('/tmp/api.so') print "result: %d" %(plib.add(1,2)) 系统调用虽然需求好像有点...“过份”,但是强大的python是可以调用诸如ioctl这类的Linux系统调用的, 以下的例子是让蜂鸣器响: import fcntl fd = open('/dev/pwm', 'r') fcntl.ioctl...
首先,创建一个C/C++文件(如I2CDebug.c),我们需要使用JNI来编写读取和写入I2C的函数: #include<jni.h>#include<linux/i2c-dev.h>#include<fcntl.h>#include<stdio.h>#include<unistd.h>JNIEXPORT jint JNICALLJava_com_example_I2CDebug_readI2C(JNIEnv*env,jobject obj,jint bus,jint addr,jint reg){char...
在linux系统中所有的设备都可以采用文件的形式访问,树莓派的i2c设备位于/dev/i2c-x(对应树莓派版本2为/dev/i2c-1),可通过open,close,wirte,read和ioclt控制i2c设备。例如open为打开I2C设备,close为关闭I2C设备,wirte为向I2C设备写入字节内容,read为从I2C设备获得字节内容,ioctl可控制I2C设备的运行参数,例如从机地址...
.unlocked_ioctl=i2cdev_ioctl, .open=i2cdev_open, .release=i2cdev_release, }; res= register_chrdev(I2C_MAJOR,"i2c", &i2cdev_fops); 3. 对设备文件进行读写时,可以调用read、write或者ioctl等方法,他们都是通过调用函数i2c_transfer来实现对I2C设备的操作的 ...
(ioctl(file, I2C_SLAVE, DEVICE_ADDRESS) < 0) { printf("Failed to acquire bus access and/or talk to slave.\n"); exit(1); } // 写入数据 uint8_t write_data = 0x00; if (write(file, &write_data, 1) != 1) { printf("Failed to write to the i2c bus.\n"); } else { ...
If you want to go in to expert mode, change I2C_SLAVE to I2C_SLAVE_FORCE in the ioctl which will let you read from the client even with a driver bound. If you do this you get to keep both pieces. Building The program assumes you have a GCC called arm-linux-gnueabi-gcc in your ...
ioctl(file, I2C_SLAVE, address) 如果该设备已经有了对应的设备驱动程序,则返回失败。 ioctl(file, I2C_SLAVE_FORCE, address) 如果该设备已经有了对应的设备驱动程序 但是还是想通过 i2c-dev 驱动来访问它 则使用这个 ioctl 来指定 I2C 设备地址。
I2C VFS驱动子系统内部会将open/close/ioctl请求转换成对应硬件的HAL层接口调用,通过HAL层接口控制主控芯片对I2C控制器的参数(从设备地址、CLK等)的设定或发起I2C 读或写操作请求。 版权信息 说明 Apache license v2.0 目录结构 │── src │ └── i2c_dev.c # I2C VFS驱动程序源代码 ├── example # ...