【蓝桥杯单片机】PWM（LED亮度调节）

实验开发板为CT107D蓝桥官方板，编译环境为MDK5

#include<STC15F2K60S2.h>sbit L1 = P0^0;sbit S4 = P3^3;typedef unsigned char u8;typedef unsigned int u16;typedef unsigned long u32;void delay(u16 i){while(i --);}void Select573(u8 channel){switch(channel){case 4:P2 = (P2 & 0x1F) | 0x80;break;case 5:P2 = (P2 & 0x1F) | 0xA0;break;case 6:P2 = (P2 & 0x1F) | 0xC0;break;case 7:P2 = (P2 & 0x1F) | 0xE0;break;}}void InitSystem(){Select573(5);P0 = 0x00;Select573(4);P0 = 0xFF;}void Timer0(){TMOD = 0x01;TH0 = (65535 - 100) / 256;//0.1msTL0 = (65535 - 100) % 256;ET0 = 1;EA = 1;;}u8 PWM_count = 0;u8 PWM_Duty = 0;void Service_Timer0()interrupt 1{TH0 = (65535 - 100) / 256;//0.1msTL0 = (65535 - 100) % 256;PWM_count ++;if(PWM_count == PWM_Duty){L1 = 1;}else if(PWM_count == 100){L1 = 0;PWM_count = 0;}}u8 Key_count = 0;void Switch_PWM(){if(S4 == 0){delay(100);if(S4 == 0){switch(Key_count){case 0:L1 = 0;TR0 = 1;PWM_Duty = 10;Key_count = 1;PWM_count = 0;break;case 1:PWM_Duty = 50;Key_count = 2;PWM_count = 0;break;case 2:PWM_Duty = 90;Key_count = 3;PWM_count = 0;break;case 3:L1 = 1;TR0 = 0;Key_count = 0;PWM_count = 0;break;}while(S4 == 0);}}}void main(){InitSystem();Timer0();while(1){Switch_PWM();}}