/////////PCA CEX0為50HZ PWM 輸出模式，PCA時鐘為外部輸入//////////////
/////////PWM2.c//////////////////////////
#include <C8051F040.h>
#define T3RUN temppage=SFRPAGE;SFRPAGE=0x01;TR3=1;SFRPAGE=temppage
#define T3STOP temppage=SFRPAGE;SFRPAGE=0x01;TR3=0;SFRPAGE=temppage
typedef unsigned int uint;
typedef unsigned char uchar;
typedef unsigned long ulong;
sfr16 RCAP2=0xca;
sfr16 RCAP3=0xca;
sfr16 RCAP4=0xca;
sfr16 TMR4=0xcc;
sfr16 TMR3=0xcc;
sfr16 TMR2=0xcc;
sfr16 PCA0CP0=0xfb;
sfr16 PCA0CP1=0xfd;
sfr16 PCA0CP2=0xe9;
sfr16 PCA0CP3=0xeb;
sfr16 PCA0CP4=0xed;
sfr16 PCA0CP5=0xe1;
uchar temppage;
void t3_fre_set(uint val){//T3頻率設(shè)置，計算公式為:(T3時鐘頻率/(2*val))
	temppage=SFRPAGE;
	SFRPAGE=0x01;
	RCAP3=~val+1;
	TMR3=RCAP3;
	SFRPAGE=temppage;
}
void t3_ini(){//t3為頻率輸出模式
	temppage=SFRPAGE;
	SFRPAGE=0x01;
	TMR3CN=0x00;//TR3=0,T3尚未啟動
	TMR3CF=0x06;//T3采用系統(tǒng)時鐘12分頻，TOG3=1,T3不計數(shù)時輸出為1，DCEN=0
	SFRPAGE=temppage;
}
void delay1ms(uint time){//延遲1ms
	uint i;
	uint j;
	for (i=0;i<time;i++){
		for(j=0;j<300;j++);
	}
}	
void pca0ini(){//CEX0為8bit PWM輸出模式
	SFRPAGE = 0x00;
	PCA0CPM0=0X42;
}
void PWM0_set(uchar low){//占空比設(shè)置，高電平占空比為(256-low)/256
	SFRPAGE = 0x00;
	PCA0CPH0=low;
}
void pcaini(){
	SFRPAGE=0x00;
	PCA0MD=0x06;//PCA采用ECI輸入時鐘，且PCA溢出中斷禁止
	PCA0CN=0x40;//啟動PCA計數(shù)器
	//EIE1|=0x08;//將此代碼屏蔽，禁止PCA中斷
}
void config(){
//看門狗禁止
	WDTCN = 0x07;	
    WDTCN = 0xDE;   
   	WDTCN = 0xAD;
	SFRPAGE = 0x0F;
//交叉開關(guān)配置，CEX0-CEX5配置到P0.0-P0.5，ECI為P0.6口，T3為P0.7口
	XBR0 = 0x70;	
	XBR1 = 0x00;	
	XBR2 = 0x40;
 	XBR3 = 0x01;   
//管腳輸出配置，P0口為開漏輸出，其中P0.6接上拉電阻，P0為數(shù)字輸入口
 	SFRPAGE = 0x0F;
 	P0MDOUT = 0x00; 
 	P1MDIN = 0xFF;  
//晶振配置，采用內(nèi)部晶振4分頻
	SFRPAGE = 0x0F;
 	CLKSEL = 0x00;  
	OSCXCN = 0x00;	
	OSCICN = 0x81;	
}
void main(void){
	xdata uchar lowset;
	config();
	t3_ini();
	t3_fre_set(239);//T3產(chǎn)生約為12800HZ的方波
	T3RUN;
	pcaini();
	pca0ini();
	lowset=0;
	PWM0_set(lowset);
	while(1){
		delay1ms(1000);
		lowset+=10;
		PWM0_set(lowset);
	}

}