71 lines
2.1 KiB
C
71 lines
2.1 KiB
C
/*
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* Copyright (c) 2006-2023, RT-Thread Development Team
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Change Logs:
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* Date Author Notes
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* 2023-3-27 wcx1024979076 first version.
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*/
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/*
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* 程序清单：这是一个 PWM 设备使用例程
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* 例程导出了 pwm_led_sample 命令到控制终端
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* 命令调用格式：pwm_led_sample
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* 程序功能：通过 PWM 设备控制 LED 灯的亮度，可以看到LED不停的由暗变到亮，然后又从亮变到暗。
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*/
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#include <rtthread.h>
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#include <rtdevice.h>
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#ifdef RT_USING_PWM
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#define LED_PIN_NUM 8 /* LED PIN脚编号，查看驱动文件drv_gpio.c确定 */
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#define PWM_DEV_NAME "pwm" /* PWM设备名称 */
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#define PWM_DEV_CHANNEL 0 /* PWM通道 */
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struct rt_device_pwm *pwm_dev; /* PWM设备句柄 */
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static int pwm_led_sample(int argc, char *argv[])
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{
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rt_uint32_t period, pulse, dir;
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period = 500000; /* 周期为0.5ms，单位为纳秒ns */
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dir = 1; /* PWM脉冲宽度值的增减方向 */
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pulse = 0; /* PWM脉冲宽度值，单位为纳秒ns */
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/* 查找设备 */
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pwm_dev = (struct rt_device_pwm *)rt_device_find(PWM_DEV_NAME);
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if (pwm_dev == RT_NULL)
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{
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rt_kprintf("pwm sample run failed! can't find %s device!\n", PWM_DEV_NAME);
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return -RT_ERROR;
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}
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/* 设置PWM周期和脉冲宽度默认值 */
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rt_pwm_set(pwm_dev, PWM_DEV_CHANNEL, period, pulse);
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/* 使能设备 */
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rt_pwm_enable(pwm_dev, PWM_DEV_CHANNEL);
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while (1)
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{
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rt_thread_mdelay(50);
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if (dir)
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{
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pulse += 400000; /* 从0值开始每次增加5000ns */
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}
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else
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{
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pulse -= 400000; /* 从最大值开始每次减少5000ns */
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}
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if (pulse >= period)
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{
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dir = 0;
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}
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if (0 == pulse)
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{
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dir = 1;
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}
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/* 设置PWM周期和脉冲宽度 */
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rt_pwm_set(pwm_dev, PWM_DEV_CHANNEL, period, pulse);
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}
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}
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/* 导出到 msh 命令列表中 */
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MSH_CMD_EXPORT(pwm_led_sample, pwm sample);
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#endif /* RT_USING_PWM */
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