116 lines
2.0 KiB
C
116 lines
2.0 KiB
C
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#include "user_iic.h"
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/*时钟线SCL高电平时，拉低数据线SDA-------------启动
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时钟线SCL高电平时，拉高数据线SDA-------------停止*/
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//产生IIC起始信号
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void IIC_Start(void)
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{
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IIC_SDA_1();
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IIC_SCL_1();
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delay_us(4);
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IIC_SDA_0();//START:when CLK is high,DATA change form high to low
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delay_us(4);
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IIC_SCL_0();//钳住I2C总线，准备发送或接收数据
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}
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//产生IIC停止信号
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void IIC_Stop(void)
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{
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IIC_SCL_0();
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IIC_SDA_0();
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delay_us(4);
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IIC_SCL_1();
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IIC_SDA_1();
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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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uint8_t IIC_Wait_Ack(void)
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{
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uint8_t ucErrTime=0;
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IIC_SDA_1();delay_us(1);
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IIC_SCL_1();delay_us(1);
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while(READ_SDA())
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{
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ucErrTime++;
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if(ucErrTime>100)
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{
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IIC_Stop();
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return 1;
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}
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}
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IIC_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 IIC_Ack(void)
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{
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IIC_SCL_0();
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IIC_SDA_0();
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delay_us(2);
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IIC_SCL_1();
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delay_us(2);
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IIC_SCL_0();
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IIC_SDA_1();
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}
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//不产生ACK应答
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void IIC_NAck(void)
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{
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IIC_SCL_0();
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IIC_SDA_1();
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delay_us(4);
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IIC_SCL_1();
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delay_us(4);
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IIC_SCL_0();
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IIC_SDA_1();
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}
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//IIC发送一个字节
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//返回从机有无应答
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//1，有应答
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//0，无应答
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void IIC_Send_Byte(uint8_t txd)
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{
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uint8_t t;
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IIC_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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{
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IIC_SDA_1();
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}
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else {
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IIC_SDA_0();
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}
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txd<<=1;
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delay_us(2); //对TEA5767这三个延时都是必须的
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IIC_SCL_1();
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delay_us(2);;
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IIC_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，ack=0，发送nACK
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uint8_t IIC_Read_Byte(unsigned char ack)
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{
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unsigned char i,receive=0;
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for(i=0;i<8;i++ )
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{
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IIC_SCL_0();
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delay_us(2);
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IIC_SCL_1();
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receive<<=1;
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if(READ_SDA())receive++;
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delay_us(1);
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}
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if (!ack)
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IIC_NAck();//发送nACK
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else
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IIC_Ack(); //发送ACK
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return receive;
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}
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