55 lines
939 B
C
55 lines
939 B
C
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#include "Ultrasonic.h"
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#include "intrins.h"
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sbit Tx = P1 ^ 0;
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sbit Rx = P1 ^ 1;
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void Delay12us(void) //@12.000MHz
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{
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unsigned char data i;
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_nop_();
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_nop_();
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i = 33;
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while (--i)
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;
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}
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void Ut_Wave_Init()
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{
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unsigned char i;
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// <20><><EFBFBD><EFBFBD>8<EFBFBD><38>40kHz<48>ķ<EFBFBD><C4B7><EFBFBD>
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// f=40kHz->T=1/f=0.000025s=25us
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// 12.5us 1 12.5us 0
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for (i = 0; i < 8; i++)
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{
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Tx = 1;
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Delay12us();
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Tx = 0;
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Delay12us();
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}
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}
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unsigned char Ut_Wave_Data()
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{
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unsigned int time;
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TMOD &= 0x0f;
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TH1 = TL1 = 0;
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Ut_Wave_Init();
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TR1 = 1;
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while ((Rx == 1) && (TF1 == 0))
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; // <20><><EFBFBD>ݶ<EFBFBD>ȡδ<C8A1><CEB4><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>û<EFBFBD><C3BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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TR1 = 0;
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// û<><C3BB><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ݶ<EFBFBD>ȡ<EFBFBD><C8A1><EFBFBD><EFBFBD>
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if (TF1 == 0)
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{
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time = TH1 << 8 | TL1; // <20><>λΪ<CEBB><CEAA><EFBFBD><EFBFBD>
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// L=V*T/2
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return (time * 0.017); // <20><><EFBFBD>صĵ<D8B5>λ<EFBFBD><CEBB>cm
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}
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// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>϶<EFBFBD><CFB6>˴β<CBB4><CEB2><EFBFBD><EFBFBD><EFBFBD>Ч
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else
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{
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TF1 = 0;
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return 0;
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}
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}
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