如何用51单片机产生pwm 并利用pwm控制led灯的功率？

#include sfr CCON = 0xD8; sfr CMOD = 0xD9; sfr CL = 0xE9; sfr CH = 0xF9; sfr CCAP0L = 0xEA; sfr CCAP0H = 0xFA; sfr CCAPM0 = 0xDA; sfr CCAPM1 = 0xDB; #define uint unsigned int #define uchar unsigned char uchar whith_p=