PWM.rar_pwm_site:www.pudn.com_占空比设置

/////////PCA CEX0为PWM 输出模式////////////// /////////PWM.c////////////////////////// #include <C8051F040.h> 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 delay1ms(uint time){//延迟1ms uint i; uint j; for (i=0;i<time;i++){ for(j=0;j<300;j++); } } void pca0ini(){//CEX0为8bit PWM输出模式 SFRPAGE = 0x00; PCA0CPM0=0X42; } void PWM0_set(uchar low){//占空比设置，高电平占空比为(256-low)/256 SFRPAGE = 0x00; PCA0CPH0=low; } void pcaini(){ SFRPAGE=0x00; PCA0MD=0x08;//PCA采用系统时钟，且PCA溢出中断禁止 PCA0CN=0x40;//启动PCA计数器 //EIE1|=0x08;//将此代码屏蔽，禁止PCA中断 } void config(){ //看门狗禁止 WDTCN = 0x07; WDTCN = 0xDE; WDTCN = 0xAD; SFRPAGE = 0x0F; //交叉开关配置，CEX0-CEX5配置到P0.0-P0.5 XBR0 = 0x30; XBR1 = 0x00; XBR2 = 0x40; XBR3 = 0x00; //管脚输出配置，P0口为开漏输出，其中P0.6接上拉电阻，P0为数字输入口 SFRPAGE = 0x0F; P0MDOUT = 0x00; P1MDIN = 0xFF; //晶振配置，采用内部晶振8分频 SFRPAGE = 0x0F; CLKSEL = 0x00; OSCXCN = 0x00; OSCICN = 0x84; } void main(void){ xdata uchar lowset; config(); pcaini(); pca0ini(); lowset=0; PWM0_set(lowset); while(1){ delay1ms(1000); lowset+=10; PWM0_set(lowset); } }