急求用51单片机（stc89c52）利用pwm控制led灯光亮度变化的c程序，电路图如下：

#include #define uint unsigned int #define uchar unsigned char uchar count ,z; sbit key_1 = P3^7; sbit key_2 = P3^6; sbit PWM = P2^0; void key_control(); void init (); void create_PWM(uchar); void delay(uint); void main () { init (); whil