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16按键Protues原理图
- #include <regx51.h>
- void delayms(unsigned int i)
- {
- unsigned char k;
- while(i--)
- for(k=0;k<120;k++);
- }
- char scan_key ();
- void main()
- {
- unsigned char led[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e};
- unsigned char i;
- P1=0xff;
- P0=0xff;
- while(1)
- {
- i=scan_key();
- if(i==-1)continue;
- else
- P1=led[i];
- }
- }
- char scan_key ()
- {
- char i, temp,m,n;
- bit find=0;
- P2=0xf0;
- i=P0;
- i&0x0f;
- if(i!=0x0f)
- {
- delayms(10);
- i=P0;
- i&0x0f;
- if(i!=0x0f)
- {
- for(i=0;i<4;i++)
- {
- P2=0xfe<<i;
- temp=~P0;
- temp=temp&0x0f;
- if(temp!=0x00)
- {
- m=i;
- find=1;
- switch(temp)
- {
- case 0x01:n=0;break;
- case 0x02:n=1;break;
- case 0x04:n=2;break;
- case 0x08:n=3;break;
- default:break;
- }
- break;
- }
- }
- }
- }
- if(find==0) return -1;
- else return(n*4+m);
- }
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