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136 lines
1.9 KiB
136 lines
1.9 KiB
#include "myiic1.h" |
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#include "delay.h" |
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//产生MYMYIIC11起始信号 |
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void MYIIC1_Start(void) |
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{ |
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SDA1_OUT(); //sda线输出 |
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MYIIC1_SDA=1; |
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MYIIC1_SCL=1; |
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delay_us(4); |
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MYIIC1_SDA=0; //SDA 由高变低 |
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delay_us(4); |
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MYIIC1_SCL=0; //准备发送或接收数据 |
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} |
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//产生MYIIC1停止信号 |
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void MYIIC1_Stop(void) |
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{ |
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SDA1_OUT(); //sda线输出 |
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MYIIC1_SCL=0; |
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MYIIC1_SDA=0; |
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delay_us(4); |
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MYIIC1_SCL=1; //SDA 由低变高 |
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delay_us(4); |
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MYIIC1_SDA=1; //发送I2C总线结束信号 |
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delay_us(4); |
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} |
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//等待应答信号到来 |
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//返回值：1，接收应答失败 |
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// 0，接收应答成功 |
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u8 MYIIC1_Wait_Ack(void) |
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{ |
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u8 ucErrTime=0; |
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SDA1_IN(); //SDA设置为输入 |
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MYIIC1_SDA=1;delay_us(1); |
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MYIIC1_SCL=1;delay_us(1); |
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while(READ1_SDA) |
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{ |
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ucErrTime++; |
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if(ucErrTime>250) |
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{ |
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MYIIC1_Stop(); |
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return 1; |
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} |
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} |
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MYIIC1_SCL=0;//时钟输出0 |
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return 0; |
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} |
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//产生ACK应答 |
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void MYIIC1_Ack(void) |
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{ |
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MYIIC1_SCL=0; |
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SDA1_OUT(); |
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MYIIC1_SDA=0; |
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delay_us(2); |
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MYIIC1_SCL=1; |
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delay_us(2); |
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MYIIC1_SCL=0; |
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} |
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//不产生ACK应答 |
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void MYIIC1_NAck(void) |
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{ |
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MYIIC1_SCL=0; |
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SDA1_OUT(); |
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MYIIC1_SDA=1; |
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delay_us(2); |
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MYIIC1_SCL=1; |
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delay_us(2); |
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MYIIC1_SCL=0; |
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} |
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//MYIIC1发送一个字节 |
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void MYIIC1_Send_Byte(u8 txd) |
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{ |
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u8 t; |
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SDA1_OUT(); |
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MYIIC1_SCL=0;//拉低时钟开始数据传输 |
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for(t=0;t<8;t++) |
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{ |
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if((txd&0x80)>>7) |
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MYIIC1_SDA=1; |
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else |
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MYIIC1_SDA=0; |
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txd<<=1; |
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delay_us(2); |
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MYIIC1_SCL=1; |
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delay_us(2); |
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MYIIC1_SCL=0; |
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delay_us(2); |
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} |
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} |
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//读1个字节，ack=1时，发送ACK应答，ack=0，发送nACK（不应答） |
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u8 MYIIC1_Read_Byte(unsigned char ack) |
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{ |
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unsigned char i,receive=0; |
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SDA1_IN();//SDA设置为输入 |
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for(i=0;i<8;i++ ) |
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{ |
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MYIIC1_SCL=0; |
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delay_us(2); |
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MYIIC1_SCL=1; |
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receive<<=1; |
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if(READ1_SDA)receive++; |
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delay_us(1); |
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} |
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if (!ack) |
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MYIIC1_NAck();//发送nACK |
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else |
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MYIIC1_Ack(); //发送ACK |
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return receive; |
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} |
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