Rtthread学习笔记（八）RT-Thread Studio的软件I2C驱动开发

RT-Thread 的 I2C 设备驱动框架即支持硬件 I2C 也支持软件模拟 I2C。
由于软件用起来比较方便，随便设置引脚，这里尝试开启一下软件I2C。

一、步骤

1.打开RT-Thread Setting中软件模拟I2C

2.开启board.h中关于I2C的宏定义

3.直接仿照官方例程初始化读写所需的I2C设备

例子：

/*
 * Copyright (c) 2006-2020, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2020-04-18     CRJ       the first version
 */
#include "stm32f1xx_hal.h"
#include 
#include 
#include 
#include "app_i2c.h"

#define AHT10_I2C_BUS_NAME          "i2c1"  /* 传感器连接的I2C总线设备名称 */
#define AHT10_ADDR                  0x38    /* 从机地址 */
#define AHT10_CALIBRATION_CMD       0xE1    /* 校准命令 */
#define AHT10_NORMAL_CMD            0xA8    /* 一般命令 */
#define AHT10_GET_DATA              0xAC    /* 获取数据命令 */

static struct rt_i2c_bus_device *i2c_bus = RT_NULL;     /* I2C总线设备句柄 */
static rt_bool_t initialized = RT_FALSE;                /* 传感器初始化状态 */
/* 写传感器寄存器 */
static rt_err_t write_reg(struct rt_i2c_bus_device *bus, rt_uint8_t reg, rt_uint8_t *data)
{
    rt_uint8_t buf[3];
    struct rt_i2c_msg msgs;

    buf[0] = reg; //cmd
    buf[1] = data[0];
    buf[2] = data[1];

    msgs.addr = AHT10_ADDR;
    msgs.flags = RT_I2C_WR;
    msgs.buf = buf;
    msgs.len = 3;

    /* 调用I2C设备接口传输数据 */
    if (rt_i2c_transfer(bus, &msgs, 1) == 1)
    {
        return RT_EOK;
    }
    else
    {
        return -RT_ERROR;
    }
}

/* 读传感器寄存器数据 */
static rt_err_t read_regs(struct rt_i2c_bus_device *bus, rt_uint8_t len, rt_uint8_t *buf)
{
    struct rt_i2c_msg msgs;

    msgs.addr = AHT10_ADDR;
    msgs.flags = RT_I2C_RD;
    msgs.buf = buf;
    msgs.len = len;

    /* 调用I2C设备接口传输数据 */
    if (rt_i2c_transfer(bus, &msgs, 1) == 1)
    {
        return RT_EOK;
    }
    else
    {
        return -RT_ERROR;
    }
}

static void read_temp_humi(float *cur_temp, float *cur_humi)
{
    rt_uint8_t temp[6];

    write_reg(i2c_bus, AHT10_GET_DATA, 0);      /* 发送命令 */
    rt_thread_mdelay(400);
    read_regs(i2c_bus, 6, temp);                /* 获取传感器数据 */

    /* 湿度数据转换 */
    *cur_humi = (temp[1] << 12 | temp[2] << 4 | (temp[3] & 0xf0) >> 4) * 100.0 / (1 << 20);
    /* 温度数据转换 */
    *cur_temp = ((temp[3] & 0xf) << 16 | temp[4] << 8 | temp[5]) * 200.0 / (1 << 20) - 50;
}

static void aht10_init(const char *name)
{
    rt_uint8_t temp[2] = {0, 0};

    /* 查找I2C总线设备，获取I2C总线设备句柄 */
    i2c_bus = (struct rt_i2c_bus_device *)rt_device_find(name);

    if (i2c_bus == RT_NULL)
    {
        rt_kprintf("can't find %s device!\n", name);
    }
    else
    {
        write_reg(i2c_bus, AHT10_NORMAL_CMD, temp);
        rt_thread_mdelay(400);

        temp[0] = 0x08;
        temp[1] = 0x00;
        write_reg(i2c_bus, AHT10_CALIBRATION_CMD, temp);
        rt_thread_mdelay(400);
        initialized = RT_TRUE;
    }
}


void Init_I2CAht10(void)
{
    float humidity, temperature;

    humidity = 0.0;
    temperature = 0.0;

    if (!initialized)
    {
        /* 传感器初始化 */
        aht10_init(AHT10_I2C_BUS_NAME);
    }
    if (initialized)
    {
        /* 读取温湿度数据 */
        read_temp_humi(&temperature, &humidity);

        rt_kprintf("read aht10 sensor humidity   : %d.%d %%\n", (int)humidity, (int)(humidity * 10) % 10);
        if( temperature >= 0 )
        {
            rt_kprintf("read aht10 sensor temperature: %d.%d°C\n", (int)temperature, (int)(temperature * 10) % 10);
        }
        else
        {
            rt_kprintf("read aht10 sensor temperature: %d.%d°C\n", (int)temperature, (int)(-temperature * 10) % 10);
        }
    }
    else
    {
        rt_kprintf("initialize sensor failed!\n");
    }

}