IIC驱动bh1750上电失败

发布于 2023-06-03 15:06:52 浏览：137 订阅该版

2 个回答

piaomiao2023 2023-06-05

这家伙很懒，什么也没写！

今天找到问题了，开始以为是IIC不工作导致的，试着加了MPU6050和BMP180的驱动进去，都能正常运行读出传感器的数据，然后在社区上找IIC和bh1750相关的帖子，看到了RTT的IIC驱动的地址是7bit，如果是8bit的地址，需要左移一位，0x46 >> 1得到0x23，把地址宏改成0x23：
```c
#define BH1750_ADDR   0x23;  // ADDR = 0x46 >> 1
```
果然能正常运行~~~~~
惊喜不！！！！
然而MPU6050和BMP180的驱动地址都是7bit，为什么bh1750的地址是8bit？？？
还有读出来的值是0，帖子上说measure_mode要设成RES_MODE2，工程上找到了已经有这个设置了，我把代码贴出来：（在下面），读出来的值还是0，也不知是不是sensor设备接口调用的是不是这个接口函数，在研究中。。。。。。
```c
float bh1750_read_light(bh1750_device_t hdev)
{
    rt_uint8_t temp[2];
    float current_light = 0;

RT_ASSERT(hdev);

bh1750_set_measure_mode(hdev, BH1750_CON_H_RES_MODE2, 120);
    bh1750_read_regs(hdev->bus, 2, temp);
    current_light = ((float)((temp[0] << 8) + temp[1]) / 1.2);

return current_light;
}
```

```
msh >[I/I2C] I2C bus [i2c2] registered

\ | /
- RT -     Thread Operating System
 / | \     4.1.0 build Jun  4 2023 21:35:19
 2006 - 2022 Copyright by RT-Thread team
[I/sensor] rt_sensor[baro_bmp180] init success
[I/sensor] rt_sensor[temp_bmp180] init success
[I/sensor] rt_sensor[li_bh1750] init success
[I/sensor.rohm.bh1750] light sensor init success
msh >sensor probe li_bh1750
[I/sensor.cmd] device id: 0xff!
msh >sensor read
[I/sensor.cmd] num:  0, light:    0 lux, timestamp:27906
[I/sensor.cmd] num:  1, light:    0 lux, timestamp:28152
[I/sensor.cmd] num:  2, light:    0 lux, timestamp:28398
[I/sensor.cmd] num:  3, light:    0 lux, timestamp:28644
[I/sensor.cmd] num:  4, light:    0 lux, timestamp:28890
msh >
```

piaomiao2023 2023-06-17

这家伙很懒，什么也没写！

关于读出来的值还是0的问题，问题已经解决了，下面是输出的传感器值：

```
msh >bh1750_sample
num:  0, light: 4391 lux, timestamp: 9454
num:  1, light: 4408 lux, timestamp: 9578
num:  2, light: 4408 lux, timestamp: 9702
num:  3, light: 4408 lux, timestamp: 9826
num:  4, light: 4400 lux, timestamp: 9950
msh >
```

修改大致三个地方：

1、`bh1750_read_light()`函数里面注释掉`bh1750_set_measure_mode()`函数。
```c
float bh1750_read_light(bh1750_device_t hdev)
{
    rt_uint8_t temp[2];
    float current_light = 0;

RT_ASSERT(hdev);

//bh1750_set_measure_mode(hdev, BH1750_CON_H_RES_MODE2, 120);
    bh1750_read_regs(hdev->bus, 2, temp);
    current_light = ((float)((temp[0] << 8) + temp[1]) / 1.2);
    return current_light;
}
```
2、`bh1750_control()`函数增加`RT_SENSOR_CTRL_SET_RANGE`和`RT_SENSOR_CTRL_SET_ODR`配置。
```c
static rt_err_t bh1750_control(struct rt_sensor_device *sensor, int cmd, void *args)
{
    rt_err_t result = RT_EOK;
    bh1750_device_t hdev = sensor->parent.user_data;

switch (cmd)
    {
        case RT_SENSOR_CTRL_SET_POWER:
        {
            result = bh1750_set_power(hdev, (rt_uint32_t)args & 0xff);
					  //rt_kprintf("bh1750_set_power:%d\n",(rt_uint32_t)args & 0xff);
            break;
        }
				case RT_SENSOR_CTRL_SET_RANGE: 
        {
					  /* 灵敏度倍率 */
					  rt_uint8_t mtreg = *(rt_uint8_t*)args & 0xff;
					
						if (mtreg <= 31)
						{
							mtreg = 31;
						}
						else if (mtreg >= 254)
						{
							mtreg = 254;
						}
						result = bh1750_write_reg(hdev->bus, 0x40 + (mtreg >> 5));
						result = bh1750_write_reg(hdev->bus, 0x40 + (mtreg & 0x1F));
            rt_kprintf("bh1750_set_range:%d\n",mtreg);
						
            break;
        }
				
				case RT_SENSOR_CTRL_SET_ODR:
        {
					 rt_uint8_t reg = *(rt_uint8_t*)args & 0xff;
            result = bh1750_write_reg(hdev->bus, reg);
					  rt_kprintf("bh1750_set_odr:%d\n",reg);
					  rt_thread_mdelay(120);
            break;
        }
        case RT_SENSOR_CTRL_SELF_TEST:
        {
            result =  -RT_EINVAL;
            break;
        }
        default:
        {
            result = -RT_ERROR;
            break;
        }
    }

return result;
}
```

3、自己实现bh1750_sample()进行传感器读取，没有使用sensor设备接口，自己写可以方便配置传感器，我是参考开发板的示例代码进行配置。
```c
static void bh1750_sample(int argc, char **argv)
{
    static rt_device_t dev = RT_NULL;
    struct rt_sensor_data data;
    rt_size_t res, i;
   
	  rt_sensor_t sensor;
    rt_int32_t delay;
	
	  rt_uint8_t reg = 0xFF;
	
	  if (dev == RT_NULL)
    {
				/* 查找系统中的传感器设备 */
				dev = rt_device_find("li_bh1750");
				if (dev == RT_NULL)
				{
						rt_kprintf("Can't find device:%s\n", argv[1]);
						return;
				}
    
				/* 以轮询模式打开传感器设备 */
				if (rt_device_open(dev, RT_DEVICE_FLAG_RDWR) != RT_EOK)
				{
						rt_kprintf("open device failed!\n");
						return;
				}
				
//				 rt_device_control(dev, RT_SENSOR_CTRL_GET_ID, ®);
//				 rt_kprintf("bh1750 device id: 0x%x!\n", reg);
				
				 reg = 69;  /* 芯片缺省灵敏度倍率 = 69 */
				 rt_device_control(dev, RT_SENSOR_CTRL_SET_RANGE, ®);
				
				 reg = BH1750_CON_H_RES_MODE2;  /* 高分辨率连续测量 */
				 rt_device_control(dev, RT_SENSOR_CTRL_SET_ODR, ®);
				
    }
		
		   sensor = (rt_sensor_t)dev;
       delay  = sensor->info.period_min > 100 ? sensor->info.period_min : 100;

for (i = 0; i < 5; i++)
        {
            res = rt_device_read(dev, 0, &data, 1);
            if (res != 1)
            {
                rt_kprintf("read data failed!size is %d\n", res);
            }
            else
            {
                sensor_show_data(i, sensor, &data);
            }
            rt_thread_mdelay(delay);
        }
				
//    /* 关闭传感器设备 */
//    rt_device_close(dev);
}
MSH_CMD_EXPORT(bh1750_sample, sensor bh1750 sample);

static void sensor_show_data(rt_size_t num, rt_sensor_t sensor, struct rt_sensor_data *sensor_data)
{
    switch (sensor->info.type)
    {

case RT_SENSOR_CLASS_LIGHT:
        rt_kprintf("num:%3d, light:%5d lux, timestamp:%5d\n", num, sensor_data->data.light, sensor_data->timestamp);
        break;
		
    default:
        break;
    }
}
```