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【NuMaker-M2354试用】I2c测试分享

发布于 2021-12-12 19:29:13 浏览：1044 订阅该版

[tocm]

## 功能模块的硬件介绍
I2C（ Inter Integrated Circuit）总线是 PHILIPS 公司开发的一种半双工、双向二线制同步串行总线。I2C 总线传输数据时只需两根信号线，一根是双向数据线 SDA（ serial data），另一根是双向时钟线 SCL（ serial clock）。 SPI 总线有两根线分别用于主从设备之间接收数据和发送数据，而 I2C 总线只使用一根线进行数据收发。
##  功能模块的使用说明
### 工程创建
rtthread的numaker-m2354工程模板是下载的其他大佬修改好了的工程，[https://gitee.com/werper/nu-maker-m2354_-test。]
### 工程裁剪
使用ENV工具，输入指令menuconfig，弹出如下界面。
![image.png](https://oss-club.rt-thread.org/uploads/20211212/ff4345128294239097d59f9a9dd71a80.png)
![image.png](https://oss-club.rt-thread.org/uploads/20211212/6439fbd52ce2f587c53352faac0f2712.png.webp)
选择Hardware Drivers Config
![image.png](https://oss-club.rt-thread.org/uploads/20211212/18c90fa6c3047e0e4072061fb2766a23.png)
然后选择On-chip peripheral Drivers
![image.png](https://oss-club.rt-thread.org/uploads/20211212/82dfaa4b2861d9d33721b91accbd681f.png)

选择I2c使能
![image.png](https://oss-club.rt-thread.org/uploads/20211212/7589e410dd2d20ab41cfb29e06cb9c56.png)
使能I2C1（我使用的是aht10传感器连接的是SDA和SCL）
![image.png](https://oss-club.rt-thread.org/uploads/20211212/53419c79b636bf69335ec15a125ad305.png.webp)
![image.png](https://oss-club.rt-thread.org/uploads/20211212/258b449a9bbe878af19a9cd5d9c6d6fe.png.webp)
### 使用I2c
官方已经很贴心的实现了I2c的驱动层，drv_I2c.c。
```
/**************************************************************************//**
*
* @copyright (C) 2020 Nuvoton Technology Corp. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date            Author         Notes
* 2020-2-05       HPHuang        First version
******************************************************************************/

#include <rtconfig.h>

#ifdef BSP_USING_I2C
#include <rtdevice.h>
#include "NuMicro.h"

/* Private define ---------------------------------------------------------------*/
#define LOG_TAG         "drv.i2c"
#define DBG_ENABLE
#define DBG_SECTION_NAME "drv.i2c"
#define DBG_LEVEL DBG_ERROR
#define DBG_COLOR
#include <rtdbg.h>

const rt_uint32_t u32I2C_MASTER_STATUS_START                  = 0x08UL;
const rt_uint32_t u32I2C_MASTER_STATUS_REPEAT_START           = 0x10UL;
const rt_uint32_t u32I2C_MASTER_STATUS_TRANSMIT_ADDRESS_ACK   = 0x18UL;
const rt_uint32_t u32I2C_MASTER_STATUS_TRANSMIT_ADDRESS_NACK  = 0x20UL;
const rt_uint32_t u32I2C_MASTER_STATUS_TRANSMIT_DATA_ACK      = 0x28UL;
const rt_uint32_t u32I2C_MASTER_STATUS_TRANSMIT_DATA_NACK     = 0x30UL;
const rt_uint32_t u32I2C_MASTER_STATUS_ARBITRATION_LOST       = 0x38UL;
const rt_uint32_t u32I2C_MASTER_STATUS_RECEIVE_ADDRESS_ACK    = 0x40UL;
const rt_uint32_t u32I2C_MASTER_STATUS_RECEIVE_ADDRESS_NACK   = 0x48UL;
const rt_uint32_t u32I2C_MASTER_STATUS_RECEIVE_DATA_ACK       = 0x50UL;
const rt_uint32_t u32I2C_MASTER_STATUS_RECEIVE_DATA_NACK      = 0x58UL;
const rt_uint32_t u32I2C_MASTER_STATUS_BUS_ERROR              = 0x00UL;
const rt_uint32_t u32I2C_MASTER_STATUS_BUS_RELEASED           = 0xF8UL;

/* Private typedef --------------------------------------------------------------*/
typedef struct _nu_i2c_bus
{
    struct rt_i2c_bus_device parent;
    I2C_T *I2C;
    struct rt_i2c_msg *msg;
    char *device_name;
} nu_i2c_bus_t;

/* Private variables ------------------------------------------------------------*/
#ifdef BSP_USING_I2C0
#define I2C0BUS_NAME  "i2c0"
static nu_i2c_bus_t nu_i2c0 =
{
    .I2C = I2C0,
    .device_name = I2C0BUS_NAME,
};
#endif /* BSP_USING_I2C0 */

#ifdef BSP_USING_I2C1
#define I2C1BUS_NAME  "i2c1"
static nu_i2c_bus_t nu_i2c1 =
{
    .I2C = I2C1,
    .device_name = I2C1BUS_NAME,
};
#endif /* BSP_USING_I2C1 */

#ifdef BSP_USING_I2C2
#define I2C2BUS_NAME  "i2c2"
static nu_i2c_bus_t nu_i2c2 =
{
    .I2C = I2C2,
    .device_name = I2C2BUS_NAME,
};
#endif /* BSP_USING_I2C2 */

/* Private functions ------------------------------------------------------------*/
#if (defined(BSP_USING_I2C0) || defined(BSP_USING_I2C1) || defined(BSP_USING_I2C2))

static rt_size_t nu_i2c_mst_xfer(struct rt_i2c_bus_device *bus,
                                 struct rt_i2c_msg msgs[],
                                 rt_uint32_t num);

static const struct rt_i2c_bus_device_ops nu_i2c_ops =
{
    .master_xfer        = nu_i2c_mst_xfer,
    .slave_xfer         = NULL,
    .i2c_bus_control    = NULL,
};

static rt_err_t nu_i2c_configure(nu_i2c_bus_t *bus)
{
    RT_ASSERT(bus != RT_NULL);

bus->parent.ops = &nu_i2c_ops;
    I2C_Open(bus->I2C, 100000);

return RT_EOK;
}

static inline rt_err_t nu_i2c_wait_ready_with_timeout(nu_i2c_bus_t *bus)
{
    rt_tick_t start = rt_tick_get();
    while (!(bus->I2C->CTL0 & I2C_CTL0_SI_Msk))
    {
        if ((rt_tick_get() - start) > bus->parent.timeout)
        {
            LOG_E("\ni2c: timeout!\n");
            return -RT_ETIMEOUT;
        }
    }

return RT_EOK;
}

static inline rt_err_t nu_i2c_send_data(nu_i2c_bus_t *nu_i2c, rt_uint8_t data)
{
    I2C_SET_DATA(nu_i2c->I2C, data);
    I2C_SET_CONTROL_REG(nu_i2c->I2C, I2C_CTL_SI);
    return nu_i2c_wait_ready_with_timeout(nu_i2c);
}

static rt_err_t nu_i2c_send_address(nu_i2c_bus_t *nu_i2c,
                                    struct rt_i2c_msg  *msg)
{
    rt_uint16_t flags = msg->flags;
    rt_uint16_t ignore_nack = msg->flags & RT_I2C_IGNORE_NACK;
    rt_uint8_t addr1, addr2;
    rt_err_t ret;

if (flags & RT_I2C_ADDR_10BIT)
    {
        nu_i2c->I2C->CTL1 |= I2C_CTL1_ADDR10EN_Msk;
        addr1 = 0xf0 | ((msg->addr >> 7) & 0x06);
        addr2 = msg->addr & 0xff;

LOG_D("address1: %d, address2: %d\n", addr1, addr2);

ret = nu_i2c_send_data(nu_i2c, addr1);
        if (ret != RT_EOK) /* for timeout condition */
            return -RT_EIO;

if ((I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_TRANSMIT_ADDRESS_ACK) && !ignore_nack)
        {
            LOG_E("NACK: sending first address failed\n");

return -RT_EIO;
        }

ret = nu_i2c_send_data(nu_i2c,  addr2);
        if (ret != RT_EOK) /* for timeout condition */
            return -RT_EIO;

if ((I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_TRANSMIT_ADDRESS_ACK) && !ignore_nack)
        {
            LOG_E("NACK: sending second address failed\n");

return -RT_EIO;
        }

if (flags & RT_I2C_RD)
        {
            LOG_D("send repeated START signal\n");

I2C_SET_CONTROL_REG(nu_i2c->I2C, I2C_CTL_STA_SI);
            ret = nu_i2c_wait_ready_with_timeout(nu_i2c);
            if (ret != RT_EOK) /* for timeout condition */
                return -RT_EIO;

if ((I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_REPEAT_START) && !ignore_nack)
            {
                LOG_E("sending repeated START failed\n");

return -RT_EIO;
            }

addr1 |= 0x01;

ret = nu_i2c_send_data(nu_i2c,  addr1);
            if (ret != RT_EOK) /* for timeout condition */
                return -RT_EIO;

if ((I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_RECEIVE_ADDRESS_ACK) && !ignore_nack)
            {
                LOG_E("NACK: sending read address failed\n");

return -RT_EIO;
            }
        }
    }
    else
    {
        /* 7-bit addr */
        addr1 = msg->addr << 1;
        if (flags & RT_I2C_RD)
            addr1 |= 1;

/* Send device address */
        ret = nu_i2c_send_data(nu_i2c,  addr1); /* Send Address */
        if (ret != RT_EOK) /* for timeout condition */
            return -RT_EIO;

if ((I2C_GET_STATUS(nu_i2c->I2C)
                != ((flags & RT_I2C_RD) ? u32I2C_MASTER_STATUS_RECEIVE_ADDRESS_ACK : u32I2C_MASTER_STATUS_TRANSMIT_ADDRESS_ACK))
                && !ignore_nack)
        {
            LOG_E("sending address failed\n");
            return -RT_EIO;
        }
    }

return RT_EOK;
}

static rt_size_t nu_i2c_mst_xfer(struct rt_i2c_bus_device *bus,
                                 struct rt_i2c_msg msgs[],
                                 rt_uint32_t num)
{
    struct rt_i2c_msg *msg;
    nu_i2c_bus_t *nu_i2c;
    rt_size_t i;
    rt_uint32_t cnt_data;
    rt_uint16_t ignore_nack;
    rt_err_t ret;

RT_ASSERT(bus != RT_NULL);
    nu_i2c = (nu_i2c_bus_t *) bus;

nu_i2c->msg = msgs;

nu_i2c->I2C->CTL0 |= I2C_CTL0_STA_Msk | I2C_CTL0_SI_Msk;
    ret = nu_i2c_wait_ready_with_timeout(nu_i2c);
    if (ret != RT_EOK) /* for timeout condition */
    {
        rt_set_errno(-RT_ETIMEOUT);
        return 0;
    }
    if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_START)
    {
        i = 0;
        LOG_E("Send START Failed");
        return i;
    }

for (i = 0; i < num; i++)
    {
        msg = &msgs[i];
        ignore_nack = msg->flags & RT_I2C_IGNORE_NACK;

if (!(msg->flags & RT_I2C_NO_START))
        {
            if (i)
            {
                I2C_SET_CONTROL_REG(nu_i2c->I2C, I2C_CTL_STA_SI);
                ret = nu_i2c_wait_ready_with_timeout(nu_i2c);
                if (ret != RT_EOK) /* for timeout condition */
                    break;

if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_REPEAT_START)
                {
                    i = 0;
                    LOG_E("Send repeat START Fail");
                    break;
                }
            }

if ((RT_EOK != nu_i2c_send_address(nu_i2c, msg))
                    && !ignore_nack)
            {
                i = 0;
                LOG_E("Send Address Fail");
                break;
            }
        }

if (nu_i2c->msg[i].flags & RT_I2C_RD) /* Receive Bytes */
        {
            rt_uint32_t do_rd_nack = (i == (num - 1));
            for (cnt_data = 0 ; cnt_data < (nu_i2c->msg[i].len) ; cnt_data++)
            {
                do_rd_nack += (cnt_data == (nu_i2c->msg[i].len - 1)); /* NACK after last byte  for hardware setting */
                if (do_rd_nack == 2)
                {
                    I2C_SET_CONTROL_REG(nu_i2c->I2C, I2C_CTL_SI);
                }
                else
                {
                    I2C_SET_CONTROL_REG(nu_i2c->I2C, I2C_CTL_SI_AA);
                }

ret = nu_i2c_wait_ready_with_timeout(nu_i2c);
                if (ret != RT_EOK) /* for timeout condition */
                    break;

if (nu_i2c->I2C->CTL0 & I2C_CTL_AA)
                {
                    if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_RECEIVE_DATA_ACK)
                    {
                        i = 0;
                        break;
                    }
                }
                else
                {
                    if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_RECEIVE_DATA_NACK)
                    {
                        i = 0;
                        break;
                    }
                }

nu_i2c->msg[i].buf[cnt_data] = nu_i2c->I2C->DAT;
            }
        }
        else /* Send Bytes */
        {
            for (cnt_data = 0 ; cnt_data < (nu_i2c->msg[i].len) ; cnt_data++)
            {
                /* Send register number and MSB of data */
                ret = nu_i2c_send_data(nu_i2c, (uint8_t)(nu_i2c->msg[i].buf[cnt_data]));
                if (ret != RT_EOK) /* for timeout condition */
                    break;

if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_TRANSMIT_DATA_ACK
                        && !ignore_nack
                   ) /* Send aata and get Ack */
                {
                    i = 0;
                    break;
                }
            }
        }
    }

I2C_STOP(nu_i2c->I2C);

RT_ASSERT(I2C_GET_STATUS(nu_i2c->I2C) == u32I2C_MASTER_STATUS_BUS_RELEASED);
    if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_BUS_RELEASED)
    {
        i = 0;
    }

nu_i2c->msg = RT_NULL;
    nu_i2c->I2C->CTL1 = 0; /*clear all sub modes like 10 bit mode*/
    return i;
}

#endif

/* Public functions -------------------------------------------------------------*/
int rt_hw_i2c_init(void)
{
    rt_err_t ret = RT_ERROR;
#if   defined(BSP_USING_I2C0)
    SYS_UnlockReg();
    SYS_ResetModule(I2C0_RST);
    SYS_LockReg();
    nu_i2c_configure(&nu_i2c0);
    ret = rt_i2c_bus_device_register(&nu_i2c0.parent, nu_i2c0.device_name);
    RT_ASSERT(RT_EOK == ret);
#endif  /* BSP_USING_I2C0 */

#if   defined(BSP_USING_I2C1)
    SYS_UnlockReg();
    SYS_ResetModule(I2C1_RST);
    SYS_LockReg();
    nu_i2c_configure(&nu_i2c1);
    ret = rt_i2c_bus_device_register(&nu_i2c1.parent, nu_i2c1.device_name);
    RT_ASSERT(RT_EOK == ret);
#endif  /* BSP_USING_I2C1 */

#if   defined(BSP_USING_I2C2)
    SYS_UnlockReg();
    SYS_ResetModule(I2C2_RST);
    SYS_LockReg();
    nu_i2c_configure(&nu_i2c2);
    ret = rt_i2c_bus_device_register(&nu_i2c2.parent, nu_i2c2.device_name);
    RT_ASSERT(RT_EOK == ret);
#endif  /* BSP_USING_I2C2 */

return ret;
}

INIT_DEVICE_EXPORT(rt_hw_i2c_init);

#endif /* BSP_USING_I2C */

```
使用官网提供的I2c测试代码，设备名称为i2c1
```
/*
 * Copyright (c) 2006-2018, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2018-08-15     misonyo      first implementation.
 */
/*
 * 程序清单：这是一个 I2C 设备使用例程
 * 例程导出了 i2c_aht10_sample 命令到控制终端
 * 命令调用格式：i2c_aht10_sample i2c1
 * 命令解释：命令第二个参数是要使用的I2C总线设备名称，为空则使用默认的I2C总线设备
 * 程序功能：通过 I2C 设备读取温湿度传感器 aht10 的温湿度数据并打印
*/
#include <rtthread.h>
#include <rtdevice.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 */
    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;
    }
}
static void i2c_aht10_sample(int argc, char *argv[])
{
    float humidity, temperature;
    char name[RT_NAME_MAX];
    humidity = 0.0;
    temperature = 0.0;
    if (argc == 2)
    {
        rt_strncpy(name, argv[1], RT_NAME_MAX);
    }
    else
    {
        rt_strncpy(name, AHT10_I2C_BUS_NAME, RT_NAME_MAX);
    }
    if (!initialized)
    {
        /* 传感器初始化 */
        aht10_init(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);
        rt_kprintf("read aht10 sensor temperature: %d.%d \n", (int)temperature, (int)(temperature * 10) % 10);
    }
    else
    {
        rt_kprintf("initialize sensor failed!\n");
    }
}
/* 导出到 msh 命令列表中 */
MSH_CMD_EXPORT(i2c_aht10_sample, i2c aht10 sample);

```
### 编译下载
在FINSH控制台下输入i2c_aht10_sample获取温度湿度
![image.png](https://oss-club.rt-thread.org/uploads/20211212/1bd164db79b39740afd7d6d428886c51.png)

## 完成模块功能的演示
观察温湿度变化，I2c测试成功
![image.png](https://oss-club.rt-thread.org/uploads/20211212/12e6c057fe54c45d2f0b1e51dfde9eb5.png.webp)
## 可编译下载的代码
[代码](https://gitee.com/tan-zhouqiang/nu-maker-m2354/tree/master/)
##心得体会
感谢给我机会来测试，I2c这块rt框架已经做好了，只需要拿来用就行，非常方便。
我也还是新手，对于rt_thread以及新唐的开发板还需要多学习专研。