一、前言
本章介绍使用安信可的esp32s3+合宙的BH1750光照传感器。
二、硬件
i2c clk – pin0
i2c sda – pin1
三、代码
#include <stdio.h>
#include "esp_log.h"
#include "driver/i2c.h"
//#include "bh1750.h"
const char *TAG = "i2c-bh1750";
#define I2C_MASTER_NUM 0 /*!< I2C master i2c port number, the number of i2c peripheral interfaces available will depend on the chip */
/*bh1750 pin*/
#define I2C_MASTER_SCL_IO 0 /*!< GPIO number used for I2C master clock */
#define I2C_MASTER_SDA_IO 1 /*!< GPIO number used for I2C master data */
#define I2C_MASTER_FREQ_HZ_SLOW 100000 /*!< I2C master clock frequency */
#define I2C_MASTER_FREQ_HZ_FAST 400000 /*!< I2C master clock frequency */
#define I2C_MASTER_TX_BUF_DISABLE 0 /*!< I2C master doesn't need buffer */
#define I2C_MASTER_RX_BUF_DISABLE 0 /*!< I2C master doesn't need buffer */
#define I2C_MASTER_TIMEOUT_MS 100
/* bh1750 addr*/
#define BH1750_SENSOR_ADDR_LOW 0x23 /*address pin low (GND) */
#define BH1750_SENSOR_ADDR_HIGH 0x24 /*address pin high (VCC) */
#define BH1750_SENSOR_ADDR BH1750_SENSOR_ADDR_LOW /*ADDR PIN (GND)*/
#define BH1750_WHO_AM_I_REG_ADDR 0x75 /*!< Register addresses of the "who am I" register */
#define BH1750_PWR_MGMT_1_REG_ADDR 0x6B /*!< Register addresses of the power managment register */
#define BH1750_RESET_BIT 7
// bh1750 registers define
#define BH1750_POWER_DOWN 0x00 // power down
#define BH1750_POWER_ON 0x01 // power on
#define BH1750_RESET 0x07 // reset
#define BH1750_CON_H_RES_MODE 0x10 // Continuously H-Resolution Mode
#define BH1750_CON_H_RES_MODE2 0x11 // Continuously H-Resolution Mode2
#define BH1750_CON_L_RES_MODE 0x13 // Continuously L-Resolution Mode
#define BH1750_ONE_H_RES_MODE 0x20 // One Time H-Resolution Mode
#define BH1750_ONE_H_RES_MODE2 0x21 // One Time H-Resolution Mode2
#define BH1750_ONE_L_RES_MODE 0x23 // One Time L-Resolution Mode
#define I2C_SEND_DELAY 10
/**
* @brief Read a sequence of bytes from a BH1750 sensor registers
*/
int bh1750_register_read(uint8_t *data, size_t len)
{
int ret=0;
ret = i2c_master_read_from_device(I2C_MASTER_NUM, BH1750_SENSOR_ADDR, data, len, I2C_MASTER_TIMEOUT_MS / portTICK_RATE_MS);
if(ret!=0)
ESP_LOGI(TAG, "%s error [%02X] \n",__FUNCTION__, ret);
return ret;
}
int bh1750_recv(uint8_t *data, size_t len)
{
int ret;
ret = bh1750_register_read(data, len);
// ESP_LOGI(TAG, "%s \t 0x[%d][%d]",__FUNCTION__,data[0],data[1]);
if(ret != 0)
ESP_LOGI(TAG, "%s error [%02X] \n",__FUNCTION__, ret);
return ret;
}
/**
* @brief Write a byte to a BH1750 sensor register
*/
int bh1750_register_write_byte(uint8_t data)
{
int ret;
uint8_t write_buf[2] = {
data, 0x00};
ret = i2c_master_write_to_device(I2C_MASTER_NUM, BH1750_SENSOR_ADDR, write_buf, 1, I2C_MASTER_TIMEOUT_MS / portTICK_RATE_MS);
return ret;
}
int bh1750_send(uint8_t data)
{
int ret;
ret = bh1750_register_write_byte(data);
if(ret != 0)
ESP_LOGI(TAG, "%s error [%d] send [%d]",__FUNCTION__, ret,data);
return ret;
}
int bh1750_send2(uint8_t data)
{
int ret;
uint8_t write_buf[2] = {
data, 0x00};
ret = i2c_master_write_to_device(I2C_MASTER_NUM, BH1750_SENSOR_ADDR, write_buf, 1, I2C_MASTER_TIMEOUT_MS / portTICK_RATE_MS);
if(ret != 0)
ESP_LOGI(TAG, "%s error [%d] send [%d]",__FUNCTION__, ret,data);
return ret;
}
void bh1750_set_measure_mode(uint8_t mode,uint8_t time)
{
// ESP_LOGI(TAG, "%s RESET ... ",__FUNCTION__);
bh1750_send(BH1750_RESET);
// ESP_LOGI(TAG, "%s SETMODE ... ",__FUNCTION__);
bh1750_send(mode);
//wait 180ms to read
// ESP_LOGI(TAG, "%s WAIT ... \n",__FUNCTION__);
vTaskDelay(pdMS_TO_TICKS(time));
}
/**
* @brief get BH1750 sensor light value
*/
void bh1750_read_light(uint8_t *data)
{
bh1750_set_measure_mode(BH1750_CON_H_RES_MODE, 180);
//get recv
bh1750_recv(data, 2);
}
/**
* @brief i2c master initialization
*/
int i2c_master_init(void)
{
int i2c_master_port = I2C_MASTER_NUM;
i2c_config_t conf = {
.mode = I2C_MODE_MASTER,
.sda_io_num = I2C_MASTER_SDA_IO,
.scl_io_num = I2C_MASTER_SCL_IO,
.sda_pullup_en = GPIO_PULLUP_ENABLE,
.scl_pullup_en = GPIO_PULLUP_ENABLE,
.master.clk_speed = I2C_MASTER_FREQ_HZ_SLOW,
};
i2c_param_config(i2c_master_port, &conf);
return i2c_driver_install(i2c_master_port, conf.mode, I2C_MASTER_RX_BUF_DISABLE, I2C_MASTER_TX_BUF_DISABLE, 0);
}
void app_main(void)
{
uint8_t data[2];
int ret = ESP_OK;
ESP_ERROR_CHECK(i2c_master_init());
ESP_LOGI(TAG, "I2C initialized successfully\n");
/*2. POWER ON*/
ret = bh1750_send(BH1750_POWER_ON);
if(ret != 0)
ESP_LOGI(TAG, "ret = %X\n",ret);
ESP_LOGI(TAG, "start test\n");
ESP_LOGI(TAG, "cmd: reset\n");
bh1750_send(BH1750_RESET);
int test=1;
while (1)
{
if(test >20)
break;
// ESP_LOGI(TAG, "test %d\n",test);
bh1750_read_light(data);
ESP_LOGI(TAG, "%s\t%d \t0x[%02x%02x] [%d]",__FUNCTION__,test,data[0],data[1],data[0]*0x100 + data[1]);
test++;
}
ESP_ERROR_CHECK(i2c_driver_delete(I2C_MASTER_NUM));
ESP_LOGI(TAG, "I2C unitialized successfully");
}
四、结果
如图，其中测试7-10是手遮挡住光感。