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RA6M4+RT-Thread PWM驱动LED

发布于 2022-07-24 16:51:27 浏览：545 订阅该版

[tocm]

# 前言
本文讲解如何使用RA6M4的硬件PWM来驱动板载LED。

# 基础
1. 我们先看一下芯片手册，板载LED是连接在P106上的，可以复用为GPT的GTIOC8B，如下图。
可以知道P106连接在了GPT168（也就是GPT8）的CH8上。

![图片1.png](https://oss-club.rt-thread.org/uploads/20220724/5f1329e9affaea4b6944452a8a6019ec.png "图片1.png")

![图片2.png](https://oss-club.rt-thread.org/uploads/20220724/e6aeb2a01d7032bb5f700c239d3e8064.png.webp "图片2.png")

2. 知道了上面的信息，我们可以开始用RA Smart Configurator来配置端口为PWM模式了，
如下，新建一个PWM定时器。

![图片3.png](https://oss-club.rt-thread.org/uploads/20220724/8837945b942199454de39f321ca577e2.png.webp "图片3.png")

3. 对新建的PWM生成器进行详细设置

![图片4.png](https://oss-club.rt-thread.org/uploads/20220724/2fa313ebe2214d74bf8d8d6ecff304f9.png.webp "图片4.png")

4. 配置GPT8端口
如下需要配置GPT8为使能状态。

![图片5.png](https://oss-club.rt-thread.org/uploads/20220724/51c2ed093f27b2b0e3ac210737ae7e37.png.webp "图片5.png")

5. 将P106端口配置为复用PWM模式

![图片6.png](https://oss-club.rt-thread.org/uploads/20220724/fc9096a880f8328825dfe8f618e0ef0b.png.webp "图片6.png")

保存生成配置代码

6. 在RT-Thread Setting中使能GPT8

![图片7.png](https://oss-club.rt-thread.org/uploads/20220724/d45c2559d07f53e65f64ac628a9eda2a.png.webp "图片7.png")

保存

# 编辑代码
代码如下：
```c
/*
 * Copyright (c) 2006-2021, RT-Thread Development Team
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Change Logs:
 * Date           Author       Notes
 * 2022-06-13     hehung       the first version
 */

#include "app_led.h"
#include <rtdevice.h>
#include <rtthread.h>
#include "hal_data.h"

#define THREAD_STACK_SIZE_LED                   (4096U)
#define THREAD_PRIORITY_LED                     (10U)
#if (LED_DRIVER_MODE == LED_MODE_IO)
#define LED3_PIN                                BSP_IO_PORT_01_PIN_06
#else
#define LED_led_pwm_dev_NAME                        ("pwm8")  /* PWM设备名称 */
#define LED_led_pwm_dev_CHANNEL                     (0)       /* PWM通道 */
#define LED_PWM_PERIOD                          (1000U)
#endif

static rt_thread_t thread_led_hd = RT_NULL;

static void Led_Thread_Entry(void *para);
static void Led_Mngr(void);
#if (LED_DRIVER_MODE == LED_MODE_IO)
static void Led_OutputIo(void);
#else
static void Led_OutputPwm(void);
#endif

/* LED线程初始化函数 */
void Led_TaskCreate(void)
{
    thread_led_hd = rt_thread_create("thread_led",
                                    Led_Thread_Entry,
                                    RT_NULL,
                                    THREAD_STACK_SIZE_LED,
                                    THREAD_PRIORITY_LED,
                                    10);
    if (RT_NULL != thread_led_hd)
    {
        rt_thread_startup(thread_led_hd);
    }
}

/* LED任务入口 */
static void Led_Thread_Entry(void *para)
{
    Led_Mngr();
}

/* LED驱动函数 */
static void Led_Mngr(void)
{
#if (LED_DRIVER_MODE == LED_MODE_IO)
    Led_OutputIo();
#else
    Led_OutputPwm();
#endif
}

#if (LED_DRIVER_MODE == LED_MODE_IO)
/* 普通IO控制LED闪烁 */
static void Led_OutputIo(void)
{
    static rt_uint8_t pin_lvl = PIN_HIGH;

while (1)
    {
        rt_pin_write(LED3_PIN, pin_lvl);

/* 反转电平 */
        pin_lvl ^= 1;

rt_thread_mdelay(500);
    }
}
#else
/* PWM控制LED闪烁 */
static void Led_OutputPwm(void)
{
    rt_uint32_t led_pwm_pulse = 0;    /* PWM占空比*/
    rt_bool_t   dir_flg = RT_FALSE;   /* PWM脉冲宽度值的增减方向 */
    /* PWM设备句柄 */
    struct rt_device_pwm *led_pwm_dev;

/* 查找设备 */
    led_pwm_dev = (struct rt_device_pwm *)rt_device_find(LED_led_pwm_dev_NAME);
    if (led_pwm_dev == RT_NULL)
    {
        rt_kprintf("led pwm run failed! can't find %s device!\n", LED_led_pwm_dev_NAME);
    }

/* 设置PWM周期和脉冲宽度默认值 */
    rt_pwm_set(led_pwm_dev, LED_led_pwm_dev_CHANNEL, LED_PWM_PERIOD, led_pwm_pulse);
    /* 使能设备 */
    rt_pwm_enable(led_pwm_dev, LED_led_pwm_dev_CHANNEL);

while (1)
    {
        led_pwm_pulse = (dir_flg) ? (led_pwm_pulse - 50) : (led_pwm_pulse + 50);

if (led_pwm_pulse >= LED_PWM_PERIOD)
        {
            dir_flg = RT_TRUE;
        }
        else if (0 == led_pwm_pulse)
        {
            dir_flg = RT_FALSE;
        }

/* 设置PWM周期和脉冲宽度 */
        rt_pwm_set(led_pwm_dev, LED_led_pwm_dev_CHANNEL, LED_PWM_PERIOD, led_pwm_pulse);

rt_thread_mdelay(50);
    }
}
#endif

```