NXP

I2C(TCA9545APWR+eeprom(AT24C04YI)

2019-07-12 11:41发布

站内文章 / NXP MCU
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devicetree: i2c-switch@70 {
compatible = "nxp,pca9545";    /* I2C switch pca9545 */


#address-cells = <0x1>;
#size-cells = <0x0>;
reg = <0x70>;


i2c@0 {
reg = <0x0>;
#address-cells = <0x1>;
#size-cells = <0x0>;
eeprom@56 {
compatible = "at,24c04";
reg = <0x56>;
};
}; };
kernel: 将AT24驱动程序编进内核。
APP: write: echo test eeprom access write and read > /sys/bus/i2c/drivers/at24/2-0056/eeprom

read: cat /sys/bus/i2c/drivers/at24/2-0056/eeprom



APP:C #include
#include
#include
#include
#include
#include
int access_eeprom(const char* path)
{
int fd, size, len, i;
    char buf[50]= {0};
    char *bufw="Hi,this is an second eepromtest!";//要写入的数据


    len=strlen(bufw);//数据长度
    fd= open(path,O_RDWR);//打开文件
    if(fd< 0)
    {
        printf("####i2c test device open failed#### ");
        return(-1);
    }
    //写操作
    lseek(fd,0x40,SEEK_SET); //定位地址，地址是0x40
    if((size=write(fd,bufw, len))<0)//写入数据
    {
        printf("write error ");
        return 1;
    }
    printf("writeok ");
    //读操作
    lseek(fd,0x40, SEEK_SET);//准备读，首先定位地址，因为前面写入的时候更新了当前文件偏移量，所以这边需要重新定位到0x40.
    if((size=read(fd,buf,len))<0)//读数据
    {
        printf("readerror ");
        return 1;
    }
    printf("readok ");
    for(i=0; i< len; i++)
    printf("buff[%d]=%c ",i, buf[i]);//打印数据
    close(fd);


}
int main(void){
   
//access_eeprom("/sys/bus/i2c/drivers/at24/2-0056/eeprom");
//sleep(5);
access_eeprom("/sys/bus/i2c/drivers/at24/6-0056/eeprom");
    return 0;
}

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