龙芯1c库是把龙芯1c的常用外设的常用功能封装为一个库，可用于裸机编程和实时系统，类似于STM32库。Git地址：http://git.oschina.NET/caogos/OpenLoongsonLib1c

无源蜂鸣器唱歌的原理

基本原理

一般说来，单片机演奏音乐基本都是单音频率，它不包含相应幅度的谐波频率，也就是说不能象电子琴那样能奏出多种音色的声音。因此单片机奏乐只需弄清楚两个概念即可，也就是“音调”和“节拍”。音调表示一个音符唱多高的频率，节拍表示一个音符唱多长的时间。

音调

音调简介

一个音调对应一个频率。即do re mi fa so la xi。乐谱中有高音，中音和低音，每个都有do re mi fa so la xi。即总共3*7=21个频率。

// do re mi fa so la xi的低音频率(单位hz)
#define BUZZER_LOW_DO_1         (262)
#define BUZZER_LOW_RE_2         (294)
#define BUZZER_LOW_MI_3         (330)
#define BUZZER_LOW_FA_4         (349)
#define BUZZER_LOW_SO_5         (392)
#define BUZZER_LOW_LA_6         (440)
#define BUZZER_LOW_XI_7         (494)
// 中音
#define BUZZER_MIDDLE_DO_1      (523)
#define BUZZER_MIDDLE_RE_2      (587)
#define BUZZER_MIDDLE_MI_3      (659)
#define BUZZER_MIDDLE_FA_4      (698)
#define BUZZER_MIDDLE_SO_5      (784)
#define BUZZER_MIDDLE_LA_6      (880)
#define BUZZER_MIDDLE_XI_7      (988)
// 高音
#define BUZZER_HIGH_DO_1        (1047)
#define BUZZER_HIGH_RE_2        (1175)
#define BUZZER_HIGH_MI_3        (1319)
#define BUZZER_HIGH_FA_4        (1397)
#define BUZZER_HIGH_SO_5        (1568)
#define BUZZER_HIGH_LA_6        (1760)
#define BUZZER_HIGH_XI_7        (1976)

识别乐谱中的高低音

5351中的1是高音，音符1的上方有个小圆点；
615中的1也是高音；
其它的都是中音。
和高音相反，低音是在音符的底下有个小圆点。

无源蜂鸣器和有缘蜂鸣器的区别

注意，这里的“源”不是指电源。而是指震荡源。
无源蜂鸣器的特点是：
1 无源内部不带震荡源，所以如果用直流信号无法令其鸣叫。必须用2K~5K的方波去驱动它
2 声音频率可控，可以做出“多来米发索拉西”的效果。
3 在一些特例中，可以和LED复用一个控制口
有源蜂鸣器的特点是：
1 有源蜂鸣器内部带震荡源，所以只要一通电就会叫
2 程序控制方便，单片机一个高低电平就可以让其发出声音，而无源蜂鸣器却做不到。

音调的软件实现

经过前面介绍，已经知道一个音调对应一个频率，给无源蜂鸣器不同频率的方波可以唱出do re mi fa so la xi。
通常，使用硬件PWM产生占空比为50%的不同频率的方波来实现。
龙芯1c库中已经有现成的PWM接口可供使用，接口中PWM周期的时间单位为ns，即PWM周期T = 1000000000 / freq。另外，目前（2017年7月）龙芯1c库中浮点功能还未完善，所以需要把占空比（浮点数）手动换算为高低电平的时间长度，占空比为50%，即周期T / 2就是一个PWM波形内高低电平的时间长度。虽然，我坚信使用浮点功能早晚会调通的，龙芯1C库中的PWM接口用占空比来表示也更符合人们的习惯，但这里还是需要稍微变通一下。

// 播放指定音高
void buzzer_sound(unsigned int freq)
{buzzer_pwm.period_ns = 1000000000 / freq;buzzer_pwm.low_ns = buzzer_pwm.period_ns / 2;pwm_init(&buzzer_pwm);return ;
}

节拍

节拍简介

节拍表示一个音符唱多长的时间，即一个频率的PWM波形的持续时间。

识别乐谱中的节拍

参考百度文库的《简谱中常用的音乐记号》

在一张乐谱中，我们经常会看到这样的表达式，如1=C (4/4) 、1=G(3/4) …… 等等，这里1=C (4/4),1=G(3/4) 表示乐谱的曲调，和我们前面所谈的音调有很大的关联，4/4、3/4 就是用来表示节拍的。以3/4 为例加以说明，它表示乐谱中以四分音符为节拍，每一小结有三拍。

其中1 、2 为一拍，3、4、5为一拍，6为一拍共三拍。1 、2的时长为四分音符的一半，即为八分音符长，3、4的时长为八分音符的一半，即为十六分音符长，5的时长为四分音符的一半，即为八分音符长，6的时长为四分音符长。
一般说来，如果乐曲没有特殊说明，一拍的时长大约为400—500ms。

节拍的软件实现

根据前面介绍已经知道，节拍就是频率持续的时间。并且一拍的时间为四五百ms，这里选择一拍为400ms，那么十六分音符长为400ms / 16 = 25ms，毫秒级的延时用“龙芯1c库”中的函数delay_ms(n)实现是没问题的。

// 测试无源蜂鸣器--依次播放do re mi fa so la xi
void buzzer_test(void)
{buzzer_init();buzzer_sound(BUZZER_LOW_DO_1);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_RE_2);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_MI_3);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_FA_4);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_SO_5);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_LA_6);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_XI_7);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_stop();}

歌曲简谱

歌曲《送别》的简谱

将简谱转换为音调和节拍的数组

// 一拍的时间，单位ms
#define BUZZER_DELAY_ONE_NOTE   (400)// 简谱中一个音符的结构
typedef struct
{unsigned int freq;          // 音调(频率)，单位hzunsigned int time_ms;       // 节拍(一个音符持续的时间)，单位ms
}buzzer_note_t;
// <<送别>>的简谱
buzzer_note_t song[] = {// 长亭外{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1}, {BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2}, {BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*2},// 古道边{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*2},// 芳草碧连{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE/2},// 天{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 晚风拂柳{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},// 笛声残{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*2},// 夕阳山外{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_FA_4, BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_LOW_XI_7,    BUZZER_DELAY_ONE_NOTE/2},// 山{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 天之涯{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*2},// 地之角{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*2},// 知交半零{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE/2},// 落{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 一瓢浊酒{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},// 尽余欢{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*2},// 今宵别梦{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_FA_4, BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_LOW_XI_7,    BUZZER_DELAY_ONE_NOTE/2},// 寒{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 长亭外{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*2},// 古道边{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*2},// 芳草碧连{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE/2},// 天{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 晚风拂柳{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},// 笛声残{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*2},// 夕阳山外{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_FA_4, BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_LOW_XI_7,    BUZZER_DELAY_ONE_NOTE/2},// 山{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 结束符{0, 0}
};

如果想唱其它的歌，只需根据歌曲的简谱重新生成这个数组就行。

实现唱歌

根据前面的介绍，已经知道，使用pwm_init()控制音调的频率，使用delay_ms()控制音符的时长。再加上已经将一首歌的简谱转换为了音调和节拍的数组，那么唱歌就变成了顺序执行音调和节拍的数组。

// 播放指定音高
void buzzer_sound(unsigned int freq)
{buzzer_pwm.period_ns = 1000000000 / freq;buzzer_pwm.low_ns = buzzer_pwm.period_ns / 2;pwm_init(&buzzer_pwm);return ;
}// 停止播放
void buzzer_stop(void)
{pwm_disable(&buzzer_pwm);gpio_init(buzzer_gpio, gpio_mode_output);gpio_set(buzzer_gpio, gpio_level_high);return ;
}/** 休止符* @time_ms 休止符时间*/
void buzzer_quiet(unsigned int time_ms)
{pwm_disable(&buzzer_pwm);delay_ms(time_ms);pwm_enable(&buzzer_pwm);return ;
}// 无源蜂鸣器唱歌
void buzzer_play(void)
{int i = 0;buzzer_init();while (1){// 判断是否结束if (0 == song[i].time_ms)break;if (0 == song[i].freq){buzzer_quiet(song[i].time_ms);}else{buzzer_sound(song[i].freq);delay_ms(song[i].time_ms);            }i++;}buzzer_stop();return ;
}

实物图

无源蜂鸣器模块
VCC ---------------- 3.3V
GND ---------------- GND
I/O ---------------- GPIO47

源码清单

pwm

之前（2017年7月）裸机编程时，浮点运算还有点问题，为了避免使用浮点运算，修改了“龙芯1c库”中的pwm的部分代码。

目前（2017年9月）硬浮点功能已调通，可以直接使用浮点数，不用再进行如下修改。

pwm_init()函数的对比照，左边为蜂鸣器唱歌源码，右边为龙芯1c库中的源码。注意，等浮点运算全部调通之后，不需要这样修改，并且龙芯1c库中使用占空比这种方式更符合平常的使用习惯。

Buzzer.h

// 无源蜂鸣器唱歌的头文件#ifndef __OPENLOONGSON_BUZZER_H
#define __OPENLOONGSON_BUZZER_H// 无源蜂鸣器初始化
void buzzer_init(void);// 停止播放
void buzzer_stop(void);// 无源蜂鸣器唱歌
void buzzer_play(void);// 测试无源蜂鸣器--依次播放do re mi fa so la xi
void buzzer_test(void);#endif

Buzzer.c

// 无源蜂鸣器唱歌的源文件#include "../lib/public.h"
#include "../lib/pwm.h"
#include "../lib/gpio.h"
#include "../lib/delay.h"// do re mi fa so la xi的低音频率(单位hz)
#define BUZZER_LOW_DO_1         (262)
#define BUZZER_LOW_RE_2         (294)
#define BUZZER_LOW_MI_3         (330)
#define BUZZER_LOW_FA_4         (349)
#define BUZZER_LOW_SO_5         (392)
#define BUZZER_LOW_LA_6         (440)
#define BUZZER_LOW_XI_7         (494)
// 中音
#define BUZZER_MIDDLE_DO_1      (523)
#define BUZZER_MIDDLE_RE_2      (587)
#define BUZZER_MIDDLE_MI_3      (659)
#define BUZZER_MIDDLE_FA_4      (698)
#define BUZZER_MIDDLE_SO_5      (784)
#define BUZZER_MIDDLE_LA_6      (880)
#define BUZZER_MIDDLE_XI_7      (988)
// 高音
#define BUZZER_HIGH_DO_1        (1047)
#define BUZZER_HIGH_RE_2        (1175)
#define BUZZER_HIGH_MI_3        (1319)
#define BUZZER_HIGH_FA_4        (1397)
#define BUZZER_HIGH_SO_5        (1568)
#define BUZZER_HIGH_LA_6        (1760)
#define BUZZER_HIGH_XI_7        (1976)// 一拍的时间，单位ms
#define BUZZER_DELAY_ONE_NOTE   (400)// 简谱中一个音符的结构
typedef struct
{unsigned int freq;          // 音调(频率)，单位hzunsigned int time_ms;       // 节拍(一个音符持续的时间)，单位ms
}buzzer_note_t;
// <<送别>>的简谱
buzzer_note_t song[] = {// 长亭外{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1}, {BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2}, {BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*2},// 古道边{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*2},// 芳草碧连{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE/2},// 天{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 晚风拂柳{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},// 笛声残{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*2},// 夕阳山外{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_FA_4, BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_LOW_XI_7,    BUZZER_DELAY_ONE_NOTE/2},// 山{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 天之涯{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*2},// 地之角{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*2},// 知交半零{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE/2},// 落{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 一瓢浊酒{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},// 尽余欢{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*2},// 今宵别梦{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_FA_4, BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_LOW_XI_7,    BUZZER_DELAY_ONE_NOTE/2},// 寒{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 长亭外{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*2},// 古道边{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*2},// 芳草碧连{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE/2},// 天{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 晚风拂柳{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_MIDDLE_XI_7, BUZZER_DELAY_ONE_NOTE/2},// 笛声残{BUZZER_MIDDLE_LA_6, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_HIGH_DO_1,   BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*2},// 夕阳山外{BUZZER_MIDDLE_SO_5, BUZZER_DELAY_ONE_NOTE*1},{BUZZER_MIDDLE_RE_2, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_MI_3, BUZZER_DELAY_ONE_NOTE/2},{BUZZER_MIDDLE_FA_4, BUZZER_DELAY_ONE_NOTE*(1+1/2)},{BUZZER_LOW_XI_7,    BUZZER_DELAY_ONE_NOTE/2},// 山{BUZZER_MIDDLE_DO_1, BUZZER_DELAY_ONE_NOTE*3},{0,                  BUZZER_DELAY_ONE_NOTE*1},// 结束符{0, 0}
};unsigned int buzzer_gpio = LS1C_PWM3_GPIO47;
pwm_info_t buzzer_pwm;// 无源蜂鸣器初始化
void buzzer_init(void)
{buzzer_pwm.gpio = buzzer_gpio;buzzer_pwm.mode = PWM_MODE_NORMAL;
}// 播放指定音高
void buzzer_sound(unsigned int freq)
{buzzer_pwm.period_ns = 1000000000 / freq;buzzer_pwm.low_ns = buzzer_pwm.period_ns / 2;pwm_init(&buzzer_pwm);return ;
}// 停止播放
void buzzer_stop(void)
{pwm_disable(&buzzer_pwm);gpio_init(buzzer_gpio, gpio_mode_output);gpio_set(buzzer_gpio, gpio_level_high);return ;
}/** 休止符* @time_ms 休止符时间*/
void buzzer_quiet(unsigned int time_ms)
{pwm_disable(&buzzer_pwm);delay_ms(time_ms);pwm_enable(&buzzer_pwm);return ;
}// 测试无源蜂鸣器--依次播放do re mi fa so la xi
void buzzer_test(void)
{buzzer_init();buzzer_sound(BUZZER_LOW_DO_1);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_RE_2);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_MI_3);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_FA_4);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_SO_5);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_LA_6);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_sound(BUZZER_LOW_XI_7);delay_ms(BUZZER_DELAY_ONE_NOTE);buzzer_stop();}// 无源蜂鸣器唱歌
void buzzer_play(void)
{int i = 0;buzzer_init();while (1){// 判断是否结束if (0 == song[i].time_ms)break;if (0 == song[i].freq){buzzer_quiet(song[i].time_ms);}else{buzzer_sound(song[i].freq);delay_ms(song[i].time_ms);            }i++;}buzzer_stop();return ;
}

main.c

#include "../lib/public.h"
#include "../lib/gpio.h"
#include "../lib/delay.h"
#include "../example/test_gpio.h"
#include "../example/test_delay.h"
#include "../example/test_simulate_i2c.h"
#include "../example/test_timer.h"
#include "buzzer.h"// pmon提供的打印接口
struct callvectors *callvec;int main(int argc, char **argv, char **env, struct callvectors *cv)
{callvec = cv;// 测试无源蜂鸣器--依次播放do re mi fa so la xi
//    buzzer_test();while (1){// 无源蜂鸣器唱歌buzzer_play();// 延时一会delay_s(5);}return(0);
}

完整的代码请移步到http://pan.baidu.com/s/1dEA19GP

感谢耐心阅读！

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