Sensor（传感器）是物联网重要的一部分，“Sensor 之于物联网”就相当于“眼睛之于人类”。人类如果没有了眼睛就看不到这大千的花花世界，对于物联网来说也是一样。已经有大量的 Sensor 被开发出来供开发者选择了，如：加速度计(Accelerometer)、磁力计(Magnetometer)、陀螺仪(Gyroscope)、气压计(Barometer/pressure)、湿度计(Humidometer)等。
传感器介绍
LTR303 传感器
LTR303 是一款数字环境光传感器，通过 I²C 或 SPI 接口与外部设备进行通信，具有低功耗、高精度等特点，能够适应多种复杂的光照环境。
LTR303 内部集成了光电二极管，能够感知环境中的可见光与红外光。通过光电转换原理，将光信号转化为电信号，再经过内部的 ADC（模拟数字转换器）将模拟电信号转换为数字信号，从而实现对环境光照强度的精确测量，测量范围可达 0.01 - 88,000 lux。
作用：根据环境光强度自动调节屏幕亮度，在保证显示效果的同时降低设备功耗，提升用户体验。
MMC56X3 传感器
MMC56X3 是一系列磁传感器，采用先进的霍尔效应技术，通过 I²C 接口与主控芯片通信，具有高灵敏度、低噪声、宽工作电压范围等优势。
利用霍尔效应原理，当有磁场作用于传感器时，传感器内部的霍尔元件会产生霍尔电压，该电压与磁场强度成正比。通过对霍尔电压的精确测量和处理，MMC56X3 能够检测环境中的磁场强度和方向 。
LSM6DS 传感器
LSM6DS 是一款高性能的 6 轴惯性测量单元（IMU），集成了三轴加速度计和三轴陀螺仪，支持 I²C 和 SPI 通信接口，具有低功耗、高动态范围、高精度等特点。
加速度测量：三轴加速度计能够测量设备在三个正交方向（X、Y、Z 轴）上的加速度，通过检测内部质量块在加速度作用下产生的惯性力，将其转化为电信号，经过处理后输出加速度数据，测量范围通常可设置为 ±2g、±4g、±8g 或 ±16g
角速度测量：三轴陀螺仪用于测量设备绕三个正交轴的旋转角速度，利用科里奥利力原理，当设备旋转时，内部的振动结构会受到科里奥利力的作用，产生相应的电信号，经过处理后得到角速度数据，测量范围一般有 ±125°/s、±250°/s、±500°/s、±1000°/s 和 ±2000°/s 等多种可选 。
供电介绍
在使用 Sensor 传感器时，需先开启供电。这是因为当传感器处于休眠状态或其他非工作场景时，关闭其供电能够更有效地降低功耗。如下图所示：
在传感器的应用场景中，PA_38 与 PA_30 这两个供电引脚必须被同步激活。这一操作具有不可替代性，因为它们分别控制着传感器的电源系统。若其中任一引脚未被激活，将直接导致传感器因供电不足而无法启动，从而无法通讯。
硬件连接
我们查看一下立创黄山派的原理图，发现各传感器都是使用PA_39_I2C3_SDA 与PA_40_I2C3_SLC进行数据的接收与发送,外设总线使用的是I2C3。
程序讲解
GPIO初始
初始化供电IO与I2C通信的引脚PA_39和PA_40设置为上拉模式
c
static void board_io_init(void)
{
HAL_PIN_Set(PAD_PA40, I2C3_SCL, PIN_PULLUP, 1);
HAL_PIN_Set(PAD_PA39, I2C3_SDA, PIN_PULLUP, 1);
rt_base_t vsys = GET_PIN(1,38);
rt_pin_mode(vsys, PIN_MODE_OUTPUT);
rt_pin_write(vsys, PIN_HIGH);
rt_base_t pin_id = GET_PIN(1,30);
rt_pin_mode(pin_id, PIN_MODE_OUTPUT);
rt_pin_write(pin_id, PIN_HIGH);
rt_thread_mdelay(50);
}1
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初始化传感器
想要初始化传感器，我们需要一个初始化函数，在工程中我们有如下代码：
c
static void sensors_init(struct rt_sensor_config *cfg)
{
cfg->intf.dev_name = "i2c3";
rt_hw_ltr303_init("ltr303", cfg);
rt_hw_mmc56x3_init("mmc56x3", cfg);
cfg->intf.user_data = (void *)LSM6DSL_ADDR_DEFAULT;
cfg->irq_pin.pin = RT_PIN_NONE;
rt_hw_lsm6dsl_init("lsm6d", cfg);
}1
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打开与配置传感器
c
static void open_and_config_devices(rt_device_t *ltr303_dev, rt_device_t *mmc56x3_dev,
rt_device_t *lsm6d_dev, rt_device_t *lsm6d_gyro_dev, rt_device_t *lsm6d_step_dev)
{
*ltr303_dev = rt_device_find("li_ltr303");
if (*ltr303_dev == RT_NULL)
rt_kprintf("Can't find device:%s\n", "ltr303");
else {
rt_err_t ret = rt_device_open(*ltr303_dev, RT_DEVICE_FLAG_RDONLY);
if (ret != RT_EOK)
rt_kprintf("open device failed! err: %d\n", ret);
rt_device_control(*ltr303_dev, RT_SENSOR_CTRL_SET_POWER, (void *)RT_SENSOR_POWER_NORMAL);
}
*mmc56x3_dev = rt_device_find("mag_mmc56x3");
if (*mmc56x3_dev == RT_NULL)
rt_kprintf("Can't find device:%s\n", "mmc56x3");
else {
rt_err_t ret = rt_device_open(*mmc56x3_dev, RT_DEVICE_FLAG_RDONLY);
if (ret != RT_EOK)
rt_kprintf("open device failed! err: %d\n", ret);
}
*lsm6d_dev = rt_device_find("acce_lsm");
*lsm6d_gyro_dev = rt_device_find("gyro_lsm");
*lsm6d_step_dev = rt_device_find("step_lsm");
if (*lsm6d_dev == RT_NULL || *lsm6d_gyro_dev == RT_NULL || *lsm6d_step_dev == RT_NULL)
rt_kprintf("Can't find device:%s\n", "lsm6d");
else {
rt_err_t ret = rt_device_open(*lsm6d_dev, RT_DEVICE_FLAG_RDONLY);
ret += rt_device_open(*lsm6d_gyro_dev, RT_DEVICE_FLAG_RDONLY);
ret += rt_device_open(*lsm6d_step_dev, RT_DEVICE_FLAG_RDONLY);
if (ret != RT_EOK)
rt_kprintf("open device failed! err: %d\n", ret);
rt_device_control(*lsm6d_dev, RT_SENSOR_CTRL_SET_ODR, (void *)1660);
rt_device_control(*lsm6d_gyro_dev, RT_SENSOR_CTRL_SET_ODR, (void *)1660);
}
}1
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- 查找传感器应用程序根据传感器设备名称获取设备句柄，进而可以操作传感器设备，查找设备函数如：*ltr303_dev = rt_device_find("li_ltr303");
- 打开传感器通过设备句柄，应用程序可以打开和关闭设备，打开设备时，会检测设备是否已经初始化，没有初始化则会默认调用初始化接口初始化设备。通过如下函数打开设备rt_err_t ret = rt_device_open(*lsm6d_dev, RT_DEVICE_FLAG_RDONLY);
- 设备模式标志参数支持下列参数：
c
#define RT_DEVICE_FLAG_RDONLY 0x001 /* 标准设备的只读模式，对应传感器的轮询模式 */
#define RT_DEVICE_FLAG_INT_RX 0x100 /* 中断接收模式 */
#define RT_DEVICE_FLAG_FIFO_RX 0x200 /* FIFO 接收模式 */1
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传感器数据接收和发送数据的模式分为 3 种：中断模式、轮询模式、FIFO 模式。在使用的时候，这 3 种模式只能选其一， 在这使用以只读及轮询模式打开传感器设备如：rt_err_t ret = rt_device_open(*ltr303_dev, RT_DEVICE_FLAG_RDONLY);
- 控制传感器设备通过命令控制字，应用程序可以对传感器设备进行配置，通过如下函数完成：rt*device_control(_ltr303_dev, RT_SENSOR_CTRL_SET_POWER, (void *)RT_SENSOR_POWER_NORMAL); 命令控制字目前支持以下几种命令控制字
c
#define RT_SENSOR_CTRL_GET_ID /* 读设备ID */
#define RT_SENSOR_CTRL_GET_INFO /* 获取设备信息 */
#define RT_SENSOR_CTRL_SET_RANGE /* 设置传感器测量范围 */
#define RT_SENSOR_CTRL_SET_ODR /* 设置传感器数据输出速率，unit is HZ */
#define RT_SENSOR_CTRL_SET_POWER /* 设置电源模式 */
#define RT_SENSOR_CTRL_SELF_TEST /* 自检 */1
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传感器数据采集与打印
读取数据可调用读取传感器接收到的数据函数如：res = rt_device_read(ltr303_dev, 0, <r303, 1);，以循环的模式读取当前数据并打印出来。
c
static void sensors_loop(rt_device_t ltr303_dev, rt_device_t mmc56x3_dev,
rt_device_t lsm6d_dev, rt_device_t lsm6d_gyro_dev, rt_device_t lsm6d_step_dev)
{
struct rt_sensor_data ltr303, mmc56x3, lsm6d_acce, lsm6d_gyro, lsm6d_step;
rt_size_t res;
res = rt_device_read(ltr303_dev, 0, <r303, 1);
if (res != 1)
rt_kprintf("read data failed!size is %d\n", res);
else
rt_kprintf("light: %d lux\n", ltr303.data.light);
res = rt_device_read(mmc56x3_dev, 0, &mmc56x3, 1);
if (res != 1)
rt_kprintf("read data failed!size is %d\n", res);
else
rt_kprintf("mag, x: %d, y: %d, z: %d\n", mmc56x3.data.mag.x, mmc56x3.data.mag.y, mmc56x3.data.mag.z);
res = rt_device_read(lsm6d_dev, 0, &lsm6d_acce, 1);
if (res != 1)
rt_kprintf("read data failed!size is %d\n", res);
else
rt_kprintf("acce, x: %d, y: %d, z: %d\n", lsm6d_acce.data.acce.x, lsm6d_acce.data.acce.y, lsm6d_acce.data.acce.z);
res = rt_device_read(lsm6d_gyro_dev, 0, &lsm6d_gyro, 1);
if (res != 1)
rt_kprintf("read data failed!size is %d\n", res);
else
rt_kprintf("gyro, x: %d, y: %d, z: %d\n", lsm6d_gyro.data.gyro.x, lsm6d_gyro.data.gyro.y, lsm6d_gyro.data.gyro.z);
res = rt_device_read(lsm6d_step_dev, 0, &lsm6d_step, 1);
if (res != 1)
rt_kprintf("read data failed!size is %d\n", res);
else
rt_kprintf("lsm6d step, step: %d\n", lsm6d_step.data.step);
rt_thread_mdelay(100);
rt_kprintf("\n");
}1
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程序编写
c
#include "rtthread.h"
#include "bf0_hal.h"
#include "drv_io.h"
#include "stdio.h"
#include "string.h"
#include "drv_gpio.h"
#include "sensor_liteon_ltr303.h"
#include "sensor_memsic_mmc56x3.h"
#include "st_lsm6dsl_sensor_v1.h"
/**
* @brief Main program
* @param None
* @retval 0 if success, otherwise failure number
*/
// 初始化硬件IO
static void board_io_init(void)
{
HAL_PIN_Set(PAD_PA40, I2C3_SCL, PIN_PULLUP, 1);
HAL_PIN_Set(PAD_PA39, I2C3_SDA, PIN_PULLUP, 1);
rt_base_t vsys = GET_PIN(1,38);
rt_pin_mode(vsys, PIN_MODE_OUTPUT);
rt_pin_write(vsys, PIN_HIGH);
rt_base_t pin_id = GET_PIN(1,30);
rt_pin_mode(pin_id, PIN_MODE_OUTPUT);
rt_pin_write(pin_id, PIN_HIGH);
rt_thread_mdelay(50);
}
// 初始化所有传感器
static void sensors_init(struct rt_sensor_config *cfg)
{
cfg->intf.dev_name = "i2c3";
rt_hw_ltr303_init("ltr303", cfg);
rt_hw_mmc56x3_init("mmc56x3", cfg);
cfg->intf.user_data = (void *)LSM6DSL_ADDR_DEFAULT;
cfg->irq_pin.pin = RT_PIN_NONE;
rt_hw_lsm6dsl_init("lsm6d", cfg);
}
// 打开并配置传感器设备
static void open_and_config_devices(rt_device_t *ltr303_dev, rt_device_t *mmc56x3_dev,
rt_device_t *lsm6d_dev, rt_device_t *lsm6d_gyro_dev, rt_device_t *lsm6d_step_dev)
{
*ltr303_dev = rt_device_find("li_ltr303");
if (*ltr303_dev == RT_NULL)
rt_kprintf("Can't find device:%s\n", "ltr303");
else {
rt_err_t ret = rt_device_open(*ltr303_dev, RT_DEVICE_FLAG_RDONLY);
if (ret != RT_EOK)
rt_kprintf("open device failed! err: %d\n", ret);
rt_device_control(*ltr303_dev, RT_SENSOR_CTRL_SET_POWER, (void *)RT_SENSOR_POWER_NORMAL);
}
*mmc56x3_dev = rt_device_find("mag_mmc56x3");
if (*mmc56x3_dev == RT_NULL)
rt_kprintf("Can't find device:%s\n", "mmc56x3");
else {
rt_err_t ret = rt_device_open(*mmc56x3_dev, RT_DEVICE_FLAG_RDONLY);
if (ret != RT_EOK)
rt_kprintf("open device failed! err: %d\n", ret);
}
*lsm6d_dev = rt_device_find("acce_lsm");
*lsm6d_gyro_dev = rt_device_find("gyro_lsm");
*lsm6d_step_dev = rt_device_find("step_lsm");
if (*lsm6d_dev == RT_NULL || *lsm6d_gyro_dev == RT_NULL || *lsm6d_step_dev == RT_NULL)
rt_kprintf("Can't find device:%s\n", "lsm6d");
else {
rt_err_t ret = rt_device_open(*lsm6d_dev, RT_DEVICE_FLAG_RDONLY);
ret += rt_device_open(*lsm6d_gyro_dev, RT_DEVICE_FLAG_RDONLY);
ret += rt_device_open(*lsm6d_step_dev, RT_DEVICE_FLAG_RDONLY);
if (ret != RT_EOK)
rt_kprintf("open device failed! err: %d\n", ret);
rt_device_control(*lsm6d_dev, RT_SENSOR_CTRL_SET_ODR, (void *)1660);
rt_device_control(*lsm6d_gyro_dev, RT_SENSOR_CTRL_SET_ODR, (void *)1660);
}
}
// 传感器数据采集与打印
static void sensors_loop(rt_device_t ltr303_dev, rt_device_t mmc56x3_dev,
rt_device_t lsm6d_dev, rt_device_t lsm6d_gyro_dev, rt_device_t lsm6d_step_dev)
{
struct rt_sensor_data ltr303, mmc56x3, lsm6d_acce, lsm6d_gyro, lsm6d_step;
rt_size_t res;
res = rt_device_read(ltr303_dev, 0, <r303, 1);
if (res != 1)
rt_kprintf("read data failed!size is %d\n", res);
else
rt_kprintf("light: %d lux\n", ltr303.data.light);
res = rt_device_read(mmc56x3_dev, 0, &mmc56x3, 1);
if (res != 1)
rt_kprintf("read data failed!size is %d\n", res);
else
rt_kprintf("mag, x: %d, y: %d, z: %d\n", mmc56x3.data.mag.x, mmc56x3.data.mag.y, mmc56x3.data.mag.z);
res = rt_device_read(lsm6d_dev, 0, &lsm6d_acce, 1);
if (res != 1)
rt_kprintf("read data failed!size is %d\n", res);
else
rt_kprintf("acce, x: %d, y: %d, z: %d\n", lsm6d_acce.data.acce.x, lsm6d_acce.data.acce.y, lsm6d_acce.data.acce.z);
res = rt_device_read(lsm6d_gyro_dev, 0, &lsm6d_gyro, 1);
if (res != 1)
rt_kprintf("read data failed!size is %d\n", res);
else
rt_kprintf("gyro, x: %d, y: %d, z: %d\n", lsm6d_gyro.data.gyro.x, lsm6d_gyro.data.gyro.y, lsm6d_gyro.data.gyro.z);
res = rt_device_read(lsm6d_step_dev, 0, &lsm6d_step, 1);
if (res != 1)
rt_kprintf("read data failed!size is %d\n", res);
else
rt_kprintf("lsm6d step, step: %d\n", lsm6d_step.data.step);
rt_thread_mdelay(100);
rt_kprintf("\n");
}
// 主函数
int main(void)
{
rt_kprintf("Hello world!\n");
board_io_init();
struct rt_sensor_config cfg;
sensors_init(&cfg);
rt_device_t ltr303_dev, mmc56x3_dev, lsm6d_dev, lsm6d_gyro_dev, lsm6d_step_dev;
open_and_config_devices(<r303_dev, &mmc56x3_dev, &lsm6d_dev, &lsm6d_gyro_dev, &lsm6d_step_dev);
while (1)
{
sensors_loop(ltr303_dev, mmc56x3_dev, lsm6d_dev, lsm6d_gyro_dev, lsm6d_step_dev);
}
return 0;
}1
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sensor配置流程
在menuconfig中打开相应传感器和I2C3
c
scons --board=sf32lb52-lchspi-ulp --menuconfig1
然后编译下载即可。