KL05Z mm8451q G_sensor 读取数据

行者无疆fw

uint8 hal_dev_mma8451_read_reg(uint8 addr)
{
    uint8 result;
    i2c_start();//设置master 模式
    i2c_write_byte(MMA8451_I2C_ADDRESS | I2C_WRITE);
    i2c_wait();//Interrupt
    i2c_get_ack();//Receive Acknowledge
    i2c_write_byte(addr);
    i2c_wait();
    i2c_get_ack();
    i2c_repeated_start();
    i2c_write_byte(MMA8451_I2C_ADDRESS | I2C_READ);
    i2c_wait();
    i2c_get_ack();
    i2c_set_rx_mode();
    i2c_give_nack(); //No acknowledge signal is sent to the bus
    result = i2c_read_byte(); //result =0x3b;
    i2c_wait();
    i2c_stop();
    result = i2c_read_byte();//result =0x00;   理论上这两次赋值，result的值应该是一样的啊，为什么赋值不一样。
    pause();
    return result;
}

uint8 i2c_read_byte(void)
{
    return I2C0->D;
}

阅读全文