帮我写一个c51单片机蜂鸣器播放生日快乐歌的代码

Sure, here's some sample code for playing the Happy Birthday song on a C51 microcontroller with a buzzer:

#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int

// Define the frequencies for each note (in Hz)
#define C 523
#define D 587
#define E 659
#define F 698
#define G 784
#define A 880
#define B 988

// Define the duration (in ms) for each note
#define QUARTER_NOTE 250
#define HALF_NOTE 500
#define WHOLE_NOTE 1000

// Define the Happy Birthday Song notes
uchar tune[] = {C, C, D, C, F, E, C, C, D, C, G, F, C, C, C, A, F, E,
                D, B, B, A, F, G, F};

uchar duration[] = {QUARTER_NOTE, QUARTER_NOTE, HALF_NOTE, HALF_NOTE, 
                    HALF_NOTE, WHOLE_NOTE, QUARTER_NOTE, QUARTER_NOTE, 
                    HALF_NOTE, HALF_NOTE, HALF_NOTE, WHOLE_NOTE, QUARTER_NOTE,
                    QUARTER_NOTE, HALF_NOTE, HALF_NOTE, HALF_NOTE, 
                    WHOLE_NOTE, QUARTER_NOTE, QUARTER_NOTE,
                    HALF_NOTE, HALF_NOTE, WHOLE_NOTE, HALF_NOTE};

// Define the buzzer output pin
sbit Buzzer = P0^0;

void delayms(uint time){ // delay function in ms
    uint i,j;
    for(i=time;i>0;i--)
        for(j=110;j>0;j--);
}

void main(){
    uchar i;
    P0 = 0x00; // Initialize output port
    
    while(1){
        for(i=0; i<sizeof(tune); i++){
            Buzzer = 1; // Turn on the buzzer
            delayms(duration[i]); // Play the note for the duration
            Buzzer = 0; // Turn off the buzzer
            delayms(10); // Add a small delay between each note
        }
        delayms(2000); // Delay for 2 seconds before playing again
    }
}

Note: This is just a simple example code, and the actual notes and duration for the song can vary. Also, make sure to connect the buzzer to the correct pin on the microcontroller and add any necessary resistors to limit the current to the buzzer.