165 lines
2.6 KiB
C
165 lines
2.6 KiB
C
#include "myiic.h"
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#include "delay.h"
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#include "bsp.h"
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//初始化IIC
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void IIC_Init(void)
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{
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GPIO_InitTypeDef GPIO_InitStructure;
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RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE); //使能GPIOB时钟
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GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
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GPIO_InitStructure.GPIO_OType = GPIO_OType_OD;
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GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
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GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
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GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9|GPIO_Pin_8;
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GPIO_Init(GPIOB, &GPIO_InitStructure);
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GPIO_SetBits(GPIOB,GPIO_Pin_9|GPIO_Pin_8); //PB6,PB7 输出高
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}
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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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SDA_OUT(); //sda线输出
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IIC_SDA_H;
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delay_us(1);
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IIC_SCL_H;
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delay_us(6);
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IIC_SDA_L;//START:when CLK is high,DATA change form high to low
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delay_us(6);
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IIC_SCL_L;//钳住I2C总线，准备发送或接收数据
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delay_us(2);
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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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SDA_OUT();//sda线输出
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IIC_SCL_L;
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IIC_SDA_L;//STOP:when CLK is high DATA change form low to high
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delay_us(5);
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IIC_SCL_H;
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delay_us(1);
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IIC_SDA_H;//发送I2C总线结束信号
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delay_us(5);
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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 IIC_Wait_Ack(void)
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{
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u32 ucErrTime=0;
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SDA_IN(); //SDA设置为输入
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// IIC_SCL_L;
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// IIC_SDA_L;
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// delay_us(5);
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IIC_SDA_H;delay_us(1);
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IIC_SCL_H;delay_us(1);
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while(READ_SDA)
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{
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delay_us(1);
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ucErrTime++;
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if(ucErrTime>250)
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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_L;//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_L;
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SDA_OUT();
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IIC_SDA_L;
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delay_us(2);
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IIC_SCL_H;
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delay_us(2);
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IIC_SCL_L;
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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_L;
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SDA_OUT();
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IIC_SDA_H;
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delay_us(2);
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IIC_SCL_H;
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delay_us(2);
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IIC_SCL_L;
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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(u8 txd)
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{
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u8 t;
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SDA_OUT();
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IIC_SCL_L;//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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//IIC_SDA=(txd&0x80)>>7;
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if((txd&0x80)>>7)
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IIC_SDA_H;
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else
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IIC_SDA_L;
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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_H;
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delay_us(2);
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IIC_SCL_L;
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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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u8 IIC_Read_Byte(unsigned char ack)
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{
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unsigned char i,receive=0;
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SDA_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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IIC_SCL_L;
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delay_us(2);
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IIC_SCL_H;
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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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