RT-Thread Studio学习（十三）DAC

一、简介

本文将基于STM32F407VET芯片介绍如何在RT-Thread Studio开发环境下使用DAC设备。硬件及开发环境如下：

• OS WIN10
• STM32F407VET6
• STM32CubeMX v6.10.0
• STM32Cube MCU Package for STM32F4 Series v1.28.0
• RT-Thread Studio v2.2.7
• RT-Thread Source Code v5.0.2
• STM32F4 chip support packages v0.2.3

二、新建RT-Thread项目并使用外部时钟

打开RT-Thread Studio软件新建基于芯片的项目，并使用外部时钟系统，具体参见《RT-Thread Studio学习（一）使用外部时钟系统》。

三、启用DAC

1. 打开DAC驱动框架
   在RT-Thread Setting 中借助图形化配置工具打开软件DAC的驱动框架，如下图所示
   
2. 定义DAC相关的宏
   在board.h文件末尾添加：

/*-------------------------- DAC CONFIG BEGIN --------------------------*/

/** if you want to use dac you can use the following instructions.
 *
 * STEP 1, open dac driver framework support in the RT-Thread Settings file
 *
 * STEP 2, define macro related to the dac
 *                 such as     #define BSP_USING_DAC1
 *
 * STEP 3, copy your dac init function from stm32xxxx_hal_msp.c generated by stm32cubemx to the end of board.c file
 *                 such as     void HAL_DAC_MspInit(DAC_HandleTypeDef* dacHandle)
 *
 * STEP 4, modify your stm32xxxx_hal_config.h file to support dac peripherals. define macro related to the peripherals
 *                 such as     #define HAL_DAC_MODULE_ENABLED
 *
 */

#define BSP_USING_DAC1

/*-------------------------- DAC CONFIG END --------------------------*/

3. 复制DAC初始化函数
   双击RT-Thread Studio工程中的cubemx.ioc文件，使能DAC1和DAC2，具体如下图：
   从使能DAC后再重新生成STM32CubeMX代码，将.\cubemx\Src\dac.c中的函数HAL_DAC_MspInit(DAC_HandleTypeDef* dacHandle)复制到board.c的末尾。

void HAL_DAC_MspInit(DAC_HandleTypeDef* dacHandle)
{

  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(dacHandle->Instance==DAC)
  {
  /* USER CODE BEGIN DAC_MspInit 0 */

  /* USER CODE END DAC_MspInit 0 */
    /* DAC clock enable */
    __HAL_RCC_DAC_CLK_ENABLE();

    __HAL_RCC_GPIOA_CLK_ENABLE();
    /**DAC GPIO Configuration
    PA4     ------> DAC_OUT1
    PA5     ------> DAC_OUT2
    */
    GPIO_InitStruct.Pin = GPIO_PIN_4|GPIO_PIN_5;
    GPIO_InitStruct.Mode = GPIO_MODE_ANALOG;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /* USER CODE BEGIN DAC_MspInit 1 */

  /* USER CODE END DAC_MspInit 1 */
  }
}

4. 定义.\cubemx\Inc\stm32f4xx_hal_conf.h中的相关宏

#define HAL_DAC_MODULE_ENABLED

四、测试

修改main.c的代码为：

/*
 * Copyright (c) 2006-2024, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2024-01-15     RT-Thread    first version
 */

#include <rtthread.h>
#include "stm32f4xx.h"
#include <rtdevice.h>

#define DBG_TAG "main"
#define DBG_LVL DBG_LOG
#include <rtdbg.h>

// PA4     ------> DAC_OUT1
// PA5     ------> DAC_OUT2
DAC_HandleTypeDef hdac;

#define DAC_DEV_NAME        "dac1"  /* DAC 设备名称 */
#define DAC_DEV_CHANNEL     1       /* DAC 通道 */
#define REFER_VOLTAGE       330         /* 参考电压 3.3V,数据精度乘以100保留2位小数*/
#define CONVERT_BITS        (1 << 12)   /* 转换位数为12位 */


// 设置dac的使用命令 dac_set dac1 1 200
// 第一个参数为命令，第二个参数为 dac 设备名称，第 3 个参数为 dac 通道，
// 第 4 个参数为 dac 输出数值
static int dac_set(int argc, char *argv[])
{
    if(argc!=4)
    {
        rt_kprintf("Usage:    dac_set <device name> <channel> <value>\n");
        rt_kprintf("Example:  dac_set dac1 1 1000\n");
        return RT_ERROR;
    }
    rt_dac_device_t dac_dev;
    rt_uint32_t value, vol, channel;
    rt_err_t ret = RT_EOK;

    char dacdevname[RT_NAME_MAX];

    rt_strncpy(dacdevname, argv[1], RT_NAME_MAX);
    channel = atoi(argv[2]);  // DAC channel
    value = atoi(argv[3]);

    /* 查找设备 */
    dac_dev = (rt_dac_device_t)rt_device_find(dacdevname);
    if (dac_dev == RT_NULL)
    {
        rt_kprintf("dac sample run failed! can't find %s device!\n", dacdevname);
        return RT_ERROR;
    }

    /* 打开通道 */
    ret = rt_dac_enable(dac_dev, channel);

    /* 设置输出值 */
    rt_dac_write(dac_dev, channel, value);
    rt_kprintf("the value is :%d \n", value);

    /* 转换为对应电压值 */
    vol = value * REFER_VOLTAGE / CONVERT_BITS;
    rt_kprintf("the voltage is :%d.%02d \n", vol / 100, vol % 100);

    /* 延时查看效果，关闭通道后无输出 */
//    rt_thread_mdelay(500);

    /* 关闭通道 */
//    ret = rt_dac_disable(dac_dev, channel);

    return ret;
}

static int dac1_vol_sample()
{
    rt_dac_device_t dac_dev;
    rt_uint32_t value, vol;
    rt_err_t ret = RT_EOK;

    /* 查找设备 */
    dac_dev = (rt_dac_device_t)rt_device_find(DAC_DEV_NAME);
    if (dac_dev == RT_NULL)
    {
        rt_kprintf("dac sample run failed! can't find %s device!\n", DAC_DEV_NAME);
        return RT_ERROR;
    }

    /* 打开通道 */
    ret = rt_dac_enable(dac_dev, DAC_DEV_CHANNEL);

    /* 设置输出值 */
    value=1000;
    rt_dac_write(dac_dev, DAC_DEV_CHANNEL, value);
    rt_kprintf("the value is :%d \n", value);

    /* 转换为对应电压值 */
    vol = value * REFER_VOLTAGE / CONVERT_BITS;
    rt_kprintf("the voltage is :%d.%02d \n", vol / 100, vol % 100);

    /* 延时查看效果，关闭通道后无输出 */
   // rt_thread_mdelay(500);

    /* 关闭通道 */
   // ret = rt_dac_disable(dac_dev, DAC_DEV_CHANNEL);

    return ret;
}

int main(void)
{
    int count = 1;
    LOG_D("Hello RT-Thread! 2024.1.17");
    LOG_D("System CLock information");
    LOG_D("SYSCLK_Frequency = %d", HAL_RCC_GetSysClockFreq());
    LOG_D("HCLK_Frequency   = %d", HAL_RCC_GetHCLKFreq());
    LOG_D("PCLK1_Frequency  = %d", HAL_RCC_GetPCLK1Freq());
    LOG_D("PCLK2_Frequency  = %d", HAL_RCC_GetPCLK2Freq());
    LOG_D("SysTick->LOAD    = %d", SysTick->LOAD);
    LOG_D("Current tick     = %d", rt_tick_get());
    dac1_vol_sample();
    while (count++)
    {
        LOG_D("Hello RT-Thread! %d", rt_tick_get());
        rt_thread_mdelay(60000);
    }

    return RT_EOK;
}

/* 导出到 msh 命令列表中 */
MSH_CMD_EXPORT(dac_set, set dac voltage. Useage: dac_set adc1 1 200);

运行结果如下：

在PA4和PA5脚用万用表测得输出电压为0.8082V

五、总结

不需要在board.h中添加#define BSP_USING_DAC2宏定义，因为dac1的通道2就是dac2。