1.IIC协议介绍

IIC全称Inter-Integrated Circuit (集成电路总线)  简称I2C
是由PHILIPS公司在80年代开发的两线式串行总线，用于连接微控制器及其外围设备。IIC属于半双工同步通信方式

特点
简单性和有效性
由于接口直接在组件之上，因此IIC总线占用的空间非常小，减少了电路板的空间和芯片管脚的数量，降低了互联成本。总线的长度可高达25英尺，并且能够以10Kbps的最大传输速率支持40个组件

多主控(multimastering)
其中任何能够进行发送和接收的设备都可以成为主总线。一个主控能够控制信号的传输和时钟频率。当然，在任何时间点上只能有一个主控。

构成

IIC串行总线一般有两根信号线，一根是双向的数据线SDA，另一根是时钟线SCL，其时钟信号是由主控器件产生。所有接到IIC总线设备上的串行数据SDA都接到总线的SDA上，各设备的时钟线SCL接到总线的SCL上。对于并联在一条总线上的每个IC都有唯一的地址。

 2.项目效果

在OLED屏幕上显示字符或者图像

3.IIC协议

就是根据IIC的时序对相应的寄存器写入数据，进行操作。

IIC总线在传输数据的过程中一共有三种类型信号，分别为：开始信号、结束信号和应答信号。
起始位，停止位，数据位，速度
这些信号中，起始信号是必需的，结束信号和应答信号

 应答信号
发送器每发送一个字节（8个bit），在时钟脉冲9期间释放数据线，由接收器反馈一个应答信号。
应答信号为低电平时，规定为有效应答位（ACK，简称应答位），表示接收器已经成功地接收了该字节；
应答信号为高电平时，规定为非应答位（NACK），一般表示接收器接收该字节没有成功。

 数据发送的时序

4.OLED写命令

 4.1 OLED的寻址模式

寻址模式的寄存器

 页地址模式

 水平地址模式

 行地址（page x）选择

 列地址选择 （分低位设置和高位设置）

主函数最后 用while(1)  卡主，不然会一直设置OLED的屏幕，一直刷新。

5.代码实现- 图

需要配合 字膜提取软件+画图工具（自带）  转换为分辨率位128x64的bmp图像。

#include "reg52.h"	
#include "intrins.h"

sbit sda=P0^3;
sbit scl=P0^1;

void i2c_start(void);   
void i2c_stop(void);
char ack(void);
void send_messege_i2c(char messege);
void w_cmd_i2c(char cmd);
void w_data_i2c(char data1);
void init_i2c(void);
void clear_oled(void);

code char tx[]={
0xFF,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,
0x01,0x03,0x03,0x03,0x07,0x07,0x05,0x07,0x03,0x03,0x03,0x03,0x03,0x03,0x03,0x01,
0x05,0x0F,0x0F,0x0F,0x07,0x05,0x07,0x05,0x07,0x07,0x07,0x0F,0x0F,0x0F,0x0F,0x0F,
0x0F,0x4F,0x0F,0x0F,0x0F,0x0F,0x0F,0x1F,0x1F,0x1F,0x0F,0x0F,0x1F,0x1F,0x1F,0x1F,
0x1F,0x3F,0x1F,0x1F,0x7F,0x1F,0x1F,0x9F,0x9F,0x3F,0x7F,0x6F,0x6F,0x5F,0x9F,0xBF,
0xBF,0xBF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x08,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x01,0x01,0x03,0x1F,0x1F,0x1F,0x3F,0x3F,0x1F,
0xCF,0xEF,0xF7,0xD7,0xDF,0xFB,0xFF,0x9F,0x9E,0x9F,0x8F,0x8F,0x9F,0x9F,0x9F,0xBF,
0xFF,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x40,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0xF0,0xF0,0xF0,0xF0,0xF8,0xF8,0xF8,0xF8,0xFC,0xFC,
0xFC,0xFC,0xFC,0xFC,0xFC,0xFC,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFC,0xE0,0xC0,0x80,
0x80,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x02,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x01,0x0C,0x44,0x60,0xF5,0xE0,0xC0,0xC0,0xC0,0xC0,0xC0,0xD8,0xFE,0xE7,0xE5,
0xFF,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x40,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x80,0xC0,0xC0,0x80,0x80,0x00,0x08,0x08,
0xC8,0x98,0x98,0x88,0x80,0x80,0xC0,0x81,0x81,0xC7,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xDF,0x87,0x87,0xC3,0xC3,0xA3,0x91,0x91,0x11,0x11,0x19,0x99,0x89,0x09,0x09,
0x01,0x83,0xC3,0xC2,0x80,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x03,0x37,0x3D,0xBF,0xBF,0x3F,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0x00,0x00,0x20,0x40,0x40,0x40,0x40,0x06,0x06,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x02,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x1E,0x3E,0x7C,0x70,0xE0,0xC3,0x1F,0x3F,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0x7F,0x7F,0x7F,0x7F,0xFF,0xFF,0xFF,
0x7F,0x7F,0x7F,0x7F,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0x1F,0x00,0x00,0x40,0x70,0x3C,0x1C,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0xC0,0xA0,0xC0,0xC0,0x00,0xC5,0xFF,0xFF,0xFF,0xFF,0xFD,0xFD,0xFF,0xFF,0xFF,
0xFF,0xFF,0x00,0x00,0x00,0x80,0x00,0x80,0x00,0x00,0xC0,0xC0,0x00,0xC0,0xC0,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x08,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x0F,0x3F,0x7F,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xDF,0x9F,0x9F,0x1F,0x1F,0x1E,0x9E,0xDE,0xDE,0xDE,0xDE,0xDE,
0xDE,0x1E,0x1C,0x1C,0x1F,0x1F,0x9F,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0x7F,0x3F,0x1F,
0x1F,0x07,0x03,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x80,0x00,0x00,0x00,
0x40,0x40,0x00,0x00,0x00,0x00,0x30,0x08,0x08,0x03,0x80,0x80,0x80,0xF8,0xF8,0xFE,
0xEF,0xC7,0xE7,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFD,0xFD,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0x00,0x00,0xE0,0xEF,0xE0,0xEF,0xE0,0x80,0x0F,0x6F,0x60,0xCF,0xAF,0xBF,
0x23,0x84,0xC0,0xA0,0xE0,0xE0,0xE0,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x02,
0x02,0x04,0x00,0x00,0x00,0x00,0x20,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x01,0x07,0x0F,0x1F,0x3F,0x3F,0x7F,0x7C,0x7C,0xF8,0xF9,0xFB,0xFB,0xFB,0xFB,0xF9,
0xF9,0x78,0x78,0x7C,0x3E,0x3F,0x1F,0x1F,0x0F,0x07,0x03,0x01,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xC1,0xE1,0xFF,0xFF,0xFE,0xFE,
0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0x00,0x00,0x9F,0xBF,0xDF,0xFF,0xFF,0xEF,0xE0,0x98,0x98,0x9A,0x87,0xA7,
0xA7,0x8F,0x8F,0x9F,0x9F,0x9A,0x9E,0x9C,0xFF,0xFB,0xFA,0xFC,0xFC,0xFC,0xEC,0xE8,
0xF8,0xF0,0xB0,0xB0,0xA0,0xE0,0xC0,0xC0,0xC0,0x80,0x80,0x80,0x80,0x00,0x00,0x20,
0x00,0x00,0x00,0x40,0xC0,0xC0,0x44,0x04,0x00,0x00,0x00,0x00,0x80,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0xC0,0xC0,0xC0,0xC0,0xC0,0xC0,0xC0,0xE0,0xE0,0xE0,0xE0,0xE0,
0xE0,0xD0,0xB0,0xF0,0xF8,0xF8,0xB8,0x9C,0xDC,0xDC,0x7E,0xFC,0xE4,0xEC,0xEC,0xF4,
0xF8,0xF8,0xFC,0xFC,0xF4,0xFE,0xFE,0xFE,0xFE,0xFF,0xFD,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};    //这是page7的内容

void main(void)
{	
	unsigned char i;
	unsigned int j;
	/*--  文字:  我  --*/
/*--  宋体12;  此字体下对应的点阵为：宽x高=16x16   --*/
	
	
	init_i2c();
	clear_oled();   //清屏函数
	
	w_cmd_i2c(0x20);  //选择页寻址模式
	w_cmd_i2c(0x02);
	
	//w_cmd_i2c(0xB0);  //选择page  1011 0xxx
	//w_cmd_i2c(0x00);    //设置起始地址  低位
	//w_cmd_i2c(0x10);    //设置起始地址  高位
	//w_data_i2c(0x80);  //发送数据

	for(i=0;i<8;i++){
		
		w_cmd_i2c(0xB0+i);    //变换page  共有0-7 8个
		w_cmd_i2c(0x00);    //设置起始地址  低位
		w_cmd_i2c(0x10);    //设置起始地址  高位
		//i=3;
		for(j=128*i; j<(128*(i+1)); j++){   //变换的是tx中的数据
			w_data_i2c(tx[j]);  //tx中的数据  
		}
	}

	while(1){}
}  
//下面是函数封装


void clear_oled(void)
{
	char i;  int j;

	for(i=0;i<8;i++){
		w_cmd_i2c(0xB0+i);    //变换page
		w_cmd_i2c(0x00);    //设置起始地址  低位
		w_cmd_i2c(0x10);    //设置起始地址  高位
		for(j=0;j<128;j++){
			w_data_i2c(0x00);  //写0就行  
		}
	}
	
}

void init_i2c(void)
{
	w_cmd_i2c(0xAE);//--display off
	w_cmd_i2c(0x00);//---set low column address
	w_cmd_i2c(0x10);//---set high column address
	w_cmd_i2c(0x40);//--set start line address 
	w_cmd_i2c(0xB0);//--set page address
	w_cmd_i2c(0x81); // contract control
	w_cmd_i2c(0xFF);//--128 
	w_cmd_i2c(0xA1);//set segment remap
	w_cmd_i2c(0xA6);//--normal / reverse
	w_cmd_i2c(0xA8);//--set multiplex ratio(1 to 64)
	w_cmd_i2c(0x3F);//--1/32 duty
	w_cmd_i2c(0xC8);//Com scan direction
	w_cmd_i2c(0xD3);//-set display offset
	w_cmd_i2c(0x00);//
	w_cmd_i2c(0xD5);//set osc division
	w_cmd_i2c(0x80);//
	w_cmd_i2c(0xD8);//set area color mode off
	w_cmd_i2c(0x05);//
	w_cmd_i2c(0xD9);//Set Pre-Charge Period
	w_cmd_i2c(0xF1);//
	w_cmd_i2c(0xDA);//set com pin configuartion
	w_cmd_i2c(0x12);//
	w_cmd_i2c(0xDB);//set Vcomh
	w_cmd_i2c(0x30);//
	w_cmd_i2c(0x8D);//set charge pump enable
	w_cmd_i2c(0x14);//
	w_cmd_i2c(0xAF);//--turn on oled panel
}

void w_cmd_i2c(char cmd)
{
	i2c_start();
	send_messege_i2c(0x78);
	ack();
	send_messege_i2c(0x00);
	ack();
	send_messege_i2c(cmd);
	ack();
	i2c_stop();
}

void w_data_i2c(char data1)
{
	i2c_start();
	send_messege_i2c(0x78);
	ack();
	send_messege_i2c(0x40);
	ack();
	send_messege_i2c(data1);
	ack();
	i2c_stop();
}

void i2c_start(void)
{
	scl=1;
	sda=0;	
	sda=1;  //我的  
	/*
	scl=0;  //老师的
	sda=1;
	scl=1;*/
	
	_nop_();   //
	sda=0;
	_nop_();   //
	scl=0;
}

void i2c_stop(void)
{
	scl=0;
	sda=0;
	scl=1;
	_nop_();   //
	sda=1;
	_nop_();   //
	sda=0;  //老师不要这个
}

char ack(void)      //应答信号
{
	char flag;
	sda=1;
	//_nop_();  //老师要的
	scl=1;
	_nop_();
	flag=sda;
	//_nop_();  //老师要的
	scl=0;
	_nop_();
	return flag;
}

void send_messege_i2c(char messege)
{
	char i;
	
	for(i=0;i<8;i++){
		scl=0;
		_nop_();   //必要
		sda= messege & 0x80 ;	
		//_nop_();  //老师要的
		scl=1;
		_nop_();
		scl=0;
		messege=messege<<1;
	}
}

6.编译的注意事项

其中的data 、xdata为ram的中的数据，可以随程序执行变化。
code中为rom中数据，调用后更改不了。5中的图片点阵太大，也不需要更改，编码在code中即可