一个红外发射程序 KEY |= 0x0f; 怎么理解？

显示全部楼层 · 2011-11-12 05:01:54

#includereg52.h#includeintrins.h#defineuintunsignedint#defineucharunsignedchar#defineKEY=P1sbitSENDTO=P3^4;uintth0tl0;ucharttimes;voidTimer0_Init(void);voidIrCoding(void);voidDelay_1ms(uchart);voidKeyScan(void);voidmain(void){SENDTO=0;Delay_1ms(200);Timer0_Init();EA=1;while(1){KeyScan();IrCoding();}}voidDelay_1ms(uchart){uchari,j;do{j=2;do{i=165;do{_nop_();}while(--i);}while(--j);}while(--t);}voidTimer0_Init(void){TMOD=0x01;ET0=0;TR0=0;}voidKeyScan(void){ucharkeystate;KEY|=0x0f;//此处不懂，运行时报错！keystate=KEY;keystate=~keystateif(keystate){Delay_1ms(200);keystate=KEY;keystate=~keystateif(keystate){if(keystateif(keystateif(keystateelseth0tl0=-4000;while(1){keystate=KEY;keystate=~keystateif(!keystate)break;}}elseth0tl0=0;}elseth0tl0=0;}voidIrCoding(void){if(!th0tl0)return;ttimes=20;TH0=th0tl0/256;TL0=th0tl0%6;ET0=1;TR0=1;while(ttimes);ET0=0;TR0=0;SENDTO=0;}voidINTT0_ISR(void){TH0=th0tl0/256;TL0=th0tl0%6;SENDTO=~SENDTO;ttimes--;}

千问 · 2011-11-12 05:01:54

我用keil运行了一下没有报错结果是这个\"csdfa\"-0Error(s),2Warning(s).上面题目中标注的语句为逻辑运算符，如下：defds123=逻辑与赋值*=乘法赋值|=逻辑或赋值/=除法赋值^=逻辑异或赋值

千问 · 2011-11-12 05:01:54

voidmain(){unsignedchari,m;m=0x22;while(1赞同