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hz
unsigned 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hz
unsigned 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！
