Linux之I2C应用编程
I2C-Tools的交叉编译
tar xvf i2c-tools-4.2.tar.xz 首先解压下压缩包
cd i2c-tools-4.2 进入 i2c-tools-4.2目录
make USE_STATIC_LIB=1 执行 make
将i2cset ,i2cget ,i2cdump,i2cdetect,i2ctransfer放到板子上
命令直接操作IIC设备
命令行直接操作iic向AP3216C传感器获取数据
基于 SMBus：
i2cset -f -y 0 0x1e 0 0x4 向0号总线的0x1e芯片地址的0号地址寄存器写入0x4
i2cset -f -y 0 0x1e 0 0x3 向0号总线的0x1e芯片地址的0号地址寄存器写入0x3
i2cget -f -y 0 0x1e 0xc 从0号总线的0x1e芯片地址的0xc号地址寄存器读一个字节
i2cget -f -y -w 0 0x1e 0xc 从0号总线的0x1e芯片地址的0xc号地址寄存器读两个字节
基于 I2C：
i2ctransfer -f -y 0 w2@0x1e 0 0x4 向0号总线的0x1e芯片地址的0号地址寄存器写入0x4 w2表示向0x1e芯片地址写入两个字节（0，0x4）
i2ctransfer -f -y 0 w2@0x1e 0 0x3 向0号总线的0x1e芯片地址的0号地址寄存器写入0x3
i2ctransfer -f -y 0 w1@0x1e 0xc r2 从0号总线的0x1e芯片地址的0xc号地址寄存器读两个字节 r2表示从 0x1e芯片地址0xc地址读寄存器读取两个字节
i2ctransfer -f -y 0 w1@0x1e 0xe r2 从0号总线的0x1e芯片地址的0xe号地址寄存器读两个字节
编写程序访问AP3216C
AP3216C 是红外、光强、距离三合一的传感器,以读出光强、距离值为例
程序
#include light
* ./AP3216C distance
*/
int main(int argc, char **argv)
{
unsigned char dev_addr = 0x1e;
unsigned char light_addr[2] = {0x0c,0x0d};
unsigned char distance_addr[2] = {0x0e,0x0f};
unsigned char buf[32];
int file;
char filename[20];
unsigned char *str;
int ret;
struct timespec req;
if (argc != 3 )
{
printf("Usage:\n");
printf(" read AP3216C: %s light/distance \n" , argv[0]);
return -1;
}
file = open_i2c_dev(argv[1][0]-'0', filename, sizeof(filename), 0);
if (file < 0)
{
printf("can't open %s\n", filename);
return -1;
}
if (set_slave_addr(file, dev_addr, 1))
{
printf("can't set_slave_addr\n");
return -1;
}
ret = i2c_smbus_write_byte_data(file, 0, 0x04);
ret = i2c_smbus_write_byte_data(file, 0, 0x03);
sleep(0.5);
if (!strcmp(argv[2],"light"))
{
//ret = i2c_smbus_read_i2c_block_data(file, light_addr[1], 2, buf);
ret = i2c_smbus_read_i2c_block_data(file, light_addr[0], 1, &buf[0]);
ret = i2c_smbus_read_i2c_block_data(file, light_addr[1], 1, &buf[1]);
if (ret < 0)
{
printf("i2c_smbus_read_i2c_block_data err\n");
return -1;
}
printf("as:%d\r\n",buf[0]);
printf("ass:%d\r\n",buf[1]);
printf("light: 0x%x%x\n", buf[0],buf[1]);
}
else if(!strcmp(argv[2],"distance"))
{
// read
ret = i2c_smbus_read_i2c_block_data(file, distance_addr[0], 1, &buf[0]);
ret = i2c_smbus_read_i2c_block_data(file, distance_addr[1], 1, &buf[1]);
if (ret < 0)
{
printf("i2c_smbus_read_i2c_block_data err\n");
return -1;
}
printf("distance: 0x%x%x\n", buf[0],buf[1]);
}
return 0;
}