IIC具体应用过程
070.9.9 IIC具体应用过程
/* ==================== main.c ==================== */
#include "reg52.h"
#include <intrins.h>
#include "delay.h"
#include "main.h"
#include "uart.h"
#include "oled.h"
uchar recv;
void main()
{
// UART_Init();
OLED_Init(); //初始化OLED
OLED_Clear();
OLED_ShowCHinese(0+10,0,0);//中
OLED_ShowCHinese(18+10,0,1);//景
OLED_ShowCHinese(36+10,0,2);//园
OLED_ShowCHinese(54+10,0,3);//电
OLED_ShowCHinese(72+10,0,4);//子
OLED_ShowCHinese(90+10,0,5);//科
OLED_ShowCHinese(18+10,2,6);//景
OLED_ShowCHinese(36+10,2,7);//园
OLED_ShowCHinese(54+10,2,8);//电
OLED_ShowCHinese(72+10,2,9);//子
while(1)
{
//OLED_Clear();
//OLED_ShowString(6,3,"I am wfeng",16);
OLED_ShowString(0,6,"STUDY:",12);
OLED_ShowString(63,6,"LERN:",12);
OLED_ShowChar(48,6,'A',16);//显示ASCII字符
OLED_ShowNum(103,6,6,3,16);
Delay_xms(1000);
}
}
/* ==================== main.h ==================== */
#ifndef _MAIN_H_
#define _MAIN_H_
#include "reg52.h"
typedef unsigned char uchar;
typedef unsigned int uint;
extern uchar recv;
sbit LED1 = P1^0;
sbit LED2 = P1^1;
sbit LED3 = P1^2;
sbit LED4 = P1^3;
sbit BEEP = P1^6;
sbit JDQ1 = P2^0;
sbit IIC_SCL = P1^5;
sbit IIC_SDA = P1^4;
#endif
/* ==================== Delay\delay.c ==================== */
#include "delay.h"
#include <intrins.h>
void Delay_xms(uint xms) //@11.0592MHz
{
uchar data i, j;
while(xms)
{
_nop_();
i = 2;
j = 199;
do
{
while (--j);
} while (--i);
xms--;
}
}
void Delay5us(void) //@11.0592MHz
{
}
/* ==================== Delay\delay.h ==================== */
#ifndef _DELAY_H_
#define _DELAY_H_
#include "main.h"
void Delay_xms(uint xms);
void Delay5us(void);
#endif
/* ==================== IIC\iic.c ==================== */
#include "iic.h"
#include "main.h"
#include "delay.h"
void IIC_Start(void)
{
IIC_SCL = 1;
IIC_SDA = 1;
Delay5us();
IIC_SDA = 0;
Delay5us();
IIC_SCL = 0;
}
void IIC_Stop(void)
{
IIC_SCL = 1;
IIC_SDA = 0;
Delay5us();
IIC_SDA = 1;
}
void IIC_Send_Byte(unsigned char IIC_Byte)
{
char i;
for(i = 0; i<8; i++)
{
IIC_SDA = IIC_Byte & (0x80 >> i);
IIC_SCL = 1;
Delay5us();
IIC_SCL = 0;
Delay5us();
}
}
unsigned char IIC_Recv_Ack(void)
{
unsigned char ack;
IIC_SDA = 1;
IIC_SCL = 1;
Delay5us();
ack = IIC_SDA;
IIC_SCL = 0;
Delay5us();
return ack;
}
/* ==================== IIC\iic.h ==================== */
#ifndef _IIC_H_
#define _IIC_H_
void IIC_Start(void);
void IIC_Stop(void);
void IIC_Send_Byte(unsigned char IIC_Byte);
unsigned char IIC_Recv_Ack(void);
#endif
/* ==================== OLED\oled.c ==================== */
#include "oled.h"
#include "oledfont.h"
#include "iic.h"
//OLED的显存
//存放格式如下.
//[0]0 1 2 3 ... 127
//[1]0 1 2 3 ... 127
//[2]0 1 2 3 ... 127
//[3]0 1 2 3 ... 127
//[4]0 1 2 3 ... 127
//[5]0 1 2 3 ... 127
//[6]0 1 2 3 ... 127
//[7]0 1 2 3 ... 127
void delay_ms(unsigned int ms)
{
unsigned int a;
while(ms)
{
a=1800;
while(a--);
ms--;
}
return;
}
/**********************************************
//IIC Start
**********************************************/
//void IIC_Start()
//{
// OLED_SCLK_Set() ;
// OLED_SDIN_Set();
// OLED_SDIN_Clr();
// OLED_SCLK_Clr();
//}
/**********************************************
//IIC Stop
**********************************************/
//void IIC_Stop()
//{
// OLED_SCLK_Set() ;
// //OLED_SCLK_Clr();
// OLED_SDIN_Clr();
// OLED_SDIN_Set();
//
//}
//void IIC_Wait_Ack()
//{
// OLED_SCLK_Set() ;
// OLED_SCLK_Clr();
//}
/**********************************************
// IIC Write byte
**********************************************/
//void Write_IIC_Byte(unsigned char IIC_Byte)
//{
// unsigned char i;
// unsigned char m,da;
// da=IIC_Byte;
// OLED_SCLK_Clr();
// for(i=0;i<8;i++)
// {
// m=da;
// // OLED_SCLK_Clr();
// m=m&0x80;
// if(m==0x80)
// {OLED_SDIN_Set();}
// else OLED_SDIN_Clr();
// da=da<<1;
// OLED_SCLK_Set();
// OLED_SCLK_Clr();
// }
//}
/**********************************************
// IIC Write Command
**********************************************/
void Write_IIC_Command(unsigned char IIC_Command)
{
IIC_Start();
IIC_Send_Byte(0x78); //Slave address,SA0=0
IIC_Recv_Ack();
IIC_Send_Byte(0x00); //write command
IIC_Recv_Ack();
IIC_Send_Byte(IIC_Command);
IIC_Recv_Ack();
IIC_Stop();
}
/**********************************************
// IIC Write Data
**********************************************/
void Write_IIC_Data(unsigned char IIC_Data)
{
IIC_Start();
IIC_Send_Byte(0x78); //D/C#=0; R/W#=0
IIC_Recv_Ack();
IIC_Send_Byte(0x40); //write data
IIC_Recv_Ack();
IIC_Send_Byte(IIC_Data);
IIC_Recv_Ack();
IIC_Stop();
}
void OLED_WR_Byte(unsigned dat,unsigned cmd)
{
if(cmd)
{
Write_IIC_Data(dat);
}
else
{
Write_IIC_Command(dat);
}
}
/********************************************
// fill_Picture
********************************************/
void fill_picture(unsigned char fill_Data)
{
unsigned char m,n;
for(m=0;m<8;m++)
{
OLED_WR_Byte(0xb0+m,0); //page0-page1
OLED_WR_Byte(0x00,0); //low column start address
OLED_WR_Byte(0x10,0); //high column start address
for(n=0;n<128;n++)
{
OLED_WR_Byte(fill_Data,1);
}
}
}
/***********************Delay****************************************/
void Delay_50ms(unsigned int Del_50ms)
{
unsigned int m;
for(;Del_50ms>0;Del_50ms--)
for(m=6245;m>0;m--);
}
void Delay_1ms(unsigned int Del_1ms)
{
unsigned char j;
while(Del_1ms--)
{
for(j=0;j<123;j++);
}
}
//坐标设置
void OLED_Set_Pos(unsigned char x, unsigned char y)
{
OLED_WR_Byte(0xb0+y,OLED_CMD);
OLED_WR_Byte(((x&0xf0)>>4)|0x10,OLED_CMD);
OLED_WR_Byte((x&0x0f),OLED_CMD);
}
//开启OLED显示
void OLED_Display_On(void)
{
OLED_WR_Byte(0X8D,OLED_CMD); //SET DCDC命令
OLED_WR_Byte(0X14,OLED_CMD); //DCDC ON
OLED_WR_Byte(0XAF,OLED_CMD); //DISPLAY ON
}
//关闭OLED显示
void OLED_Display_Off(void)
{
OLED_WR_Byte(0X8D,OLED_CMD); //SET DCDC命令
OLED_WR_Byte(0X10,OLED_CMD); //DCDC OFF
OLED_WR_Byte(0XAE,OLED_CMD); //DISPLAY OFF
}
//清屏函数,清完屏,整个屏幕是黑色的!和没点亮一样!!!
void OLED_Clear(void)
{
u8 i,n;
for(i=0;i<8;i++)
{
OLED_WR_Byte (0xb0+i,OLED_CMD); //设置页地址（0~7）
OLED_WR_Byte (0x00,OLED_CMD); //设置显示位置—列低地址
OLED_WR_Byte (0x10,OLED_CMD); //设置显示位置—列高地址
for(n=0;n<128;n++)
OLED_WR_Byte(0,OLED_DATA);
} //更新显示
}
void OLED_On(void)
{
u8 i,n;
for(i=0;i<8;i++)
{
OLED_WR_Byte (0xb0+i,OLED_CMD); //设置页地址（0~7）
OLED_WR_Byte (0x00,OLED_CMD); //设置显示位置—列低地址
OLED_WR_Byte (0x10,OLED_CMD); //设置显示位置—列高地址
for(n=0;n<128;n++)
OLED_WR_Byte(1,OLED_DATA);
} //更新显示
}
//在指定位置显示一个字符,包括部分字符
//x:0~127
//y:0~63
//mode:0,反白显示;1,正常显示
//size:选择字体 16/12
void OLED_ShowChar(u8 x,u8 y,u8 chr,u8 Char_Size)
{
unsigned char c=0,i=0;
c=chr-' ';//得到偏移后的值
if(x>Max_Column-1)
{
x=0;
y=y+2;
}
if(Char_Size ==16)
{
OLED_Set_Pos(x,y);
for(i=0;i<8;i++)
OLED_WR_Byte(F8X16[c*16+i],OLED_DATA);
OLED_Set_Pos(x,y+1);
for(i=0;i<8;i++)
OLED_WR_Byte(F8X16[c*16+i+8],OLED_DATA);
}
else
{
OLED_Set_Pos(x,y);
for(i=0;i<6;i++)
OLED_WR_Byte(F6x8[c][i],OLED_DATA);
}
}
//m^n函数
u32 oled_pow(u8 m,u8 n)
{
u32 result=1;
while(n--)
{
result*=m;
}
return result;
}
//显示2个数字
//x,y :起点坐标
//len :数字的位数
//size:字体大小
//mode:模式 0,填充模式;1,叠加模式
//num:数值(0~4294967295);
void OLED_ShowNum(u8 x,u8 y,u32 num,u8 len,u8 size2)
{
u8 t,temp;
u8 enshow=0;
for(t=0;t<len;t++)
{
temp=(num/oled_pow(10,len-t-1))%10;
if(enshow==0&&t<(len-1))
{
if(temp==0)
{
OLED_ShowChar(x+(size2/2)*t,y,' ',size2);
continue;
}
else
enshow=1;
}
OLED_ShowChar(x+(size2/2)*t,y,temp+'0',size2);
}
}
//显示一个字符号串
void OLED_ShowString(u8 x,u8 y,u8 *chr,u8 Char_Size)
{
unsigned char j=0;
while (chr[j]!='\0')
{
OLED_ShowChar(x,y,chr[j],Char_Size);
x+=8;
if(x>120){x=0;y+=2;}
j++;
}
}
//显示汉字
void OLED_ShowCHinese(u8 x,u8 y,u8 no)
{
u8 t,adder=0;
OLED_Set_Pos(x,y);
for(t=0;t<16;t++)
{
OLED_WR_Byte(Hzk[2*no][t],OLED_DATA);
adder+=1;
}
OLED_Set_Pos(x,y+1);
for(t=0;t<16;t++)
{
OLED_WR_Byte(Hzk[2*no+1][t],OLED_DATA);
adder+=1;
}
}
/***********功能描述：显示显示BMP图片128×64起始点坐标(x,y),x的范围0～127，y为页的范围0～7*****************/
void OLED_DrawBMP(unsigned char x0, unsigned char y0,unsigned char x1, unsigned char y1,unsigned char BMP[])
{
unsigned int j=0;
unsigned char x,y;
if(y1%8==0)
y=y1/8;
else
y=y1/8+1;
for(y=y0;y<y1;y++)
{
OLED_Set_Pos(x0,y);
for(x=x0;x<x1;x++)
{
OLED_WR_Byte(BMP[j++],OLED_DATA);
}
}
}
//初始化SSD1306
void OLED_Init(void)
{
OLED_WR_Byte(0xAE,OLED_CMD);//--display off
OLED_WR_Byte(0x00,OLED_CMD);//---set low column address
OLED_WR_Byte(0x10,OLED_CMD);//---set high column address
OLED_WR_Byte(0x40,OLED_CMD);//--set start line address
OLED_WR_Byte(0xB0,OLED_CMD);//--set page address
OLED_WR_Byte(0x81,OLED_CMD); // contract control
OLED_WR_Byte(0xFF,OLED_CMD);//--128
OLED_WR_Byte(0xA1,OLED_CMD);//set segment remap
OLED_WR_Byte(0xA6,OLED_CMD);//--normal / reverse
OLED_WR_Byte(0xA8,OLED_CMD);//--set multiplex ratio(1 to 64)
OLED_WR_Byte(0x3F,OLED_CMD);//--1/32 duty
OLED_WR_Byte(0xC8,OLED_CMD);//Com scan direction
OLED_WR_Byte(0xD3,OLED_CMD);//-set display offset
OLED_WR_Byte(0x00,OLED_CMD);//
OLED_WR_Byte(0xD5,OLED_CMD);//set osc division
OLED_WR_Byte(0x80,OLED_CMD);//
OLED_WR_Byte(0xD8,OLED_CMD);//set area color mode off
OLED_WR_Byte(0x05,OLED_CMD);//
OLED_WR_Byte(0xD9,OLED_CMD);//Set Pre-Charge Period
OLED_WR_Byte(0xF1,OLED_CMD);//
OLED_WR_Byte(0xDA,OLED_CMD);//set com pin configuartion
OLED_WR_Byte(0x12,OLED_CMD);//
OLED_WR_Byte(0xDB,OLED_CMD);//set Vcomh
OLED_WR_Byte(0x30,OLED_CMD);//
OLED_WR_Byte(0x8D,OLED_CMD);//set charge pump enable
OLED_WR_Byte(0x14,OLED_CMD);//
OLED_WR_Byte(0xAF,OLED_CMD);//--turn on oled panel
}
/* ==================== OLED\oled.h ==================== */
//#include "REG51.h"
#ifndef __OLED_H
#define __OLED_H
//#include "sys.h"
//#include "stdlib.h"
#define u8 unsigned char
#define u32 unsigned int
#define OLED_CMD 0 //写命令
#define OLED_DATA 1 //写数据
#define OLED_MODE 0
//sbit OLED_SCL=P1^5;//时钟 D0（SCLK?
//sbit OLED_SDIN=P1^4;//D1（MOSI） 数据
//#define OLED_SCLK_Clr() OLED_SCL=0
//#define OLED_SCLK_Set() OLED_SCL=1
//#define OLED_SDIN_Clr() OLED_SDIN=0
//#define OLED_SDIN_Set() OLED_SDIN=1
//OLED模式设置
//0:4线串行模式
//1:并行8080模式
#define SIZE 16
#define XLevelL 0x02
#define XLevelH 0x10
#define Max_Column 128
#define Max_Row 64
#define Brightness 0xFF
#define X_WIDTH 128
#define Y_WIDTH 64
//-----------------OLED端口定义----------------
void delay_ms(unsigned int ms);
//OLED控制用函数
void OLED_WR_Byte(unsigned dat,unsigned cmd);
void OLED_Display_On(void);
void OLED_Display_Off(void);
void OLED_Init(void);
void OLED_Clear(void);
void OLED_DrawPoint(u8 x,u8 y,u8 t);
void OLED_Fill(u8 x1,u8 y1,u8 x2,u8 y2,u8 dot);
void OLED_ShowChar(u8 x,u8 y,u8 chr,u8 Char_Size);
void OLED_ShowNum(u8 x,u8 y,u32 num,u8 len,u8 size);
void OLED_ShowString(u8 x,u8 y, u8 *p,u8 Char_Size);
void OLED_Set_Pos(unsigned char x, unsigned char y);
void OLED_ShowCHinese(u8 x,u8 y,u8 no);
void OLED_DrawBMP(unsigned char x0, unsigned char y0,unsigned char x1, unsigned char y1,unsigned char BMP[]);
void Delay_50ms(unsigned int Del_50ms);
void Delay_1ms(unsigned int Del_1ms);
void fill_picture(unsigned char fill_Data);
void Picture();
void IIC_Start();
void IIC_Stop();
void Write_IIC_Command(unsigned char IIC_Command);
void Write_IIC_Data(unsigned char IIC_Data);
void Write_IIC_Byte(unsigned char IIC_Byte);
void IIC_Wait_Ack();
#endif
/* ==================== OLED\oledfont.h ==================== */
#ifndef __OLEDFONT_H
#define __OLEDFONT_H
//常用ASCII表
//偏移量32
//ASCII字符集
//偏移量32
//大小:12*6
/************************************6*8的点阵************************************/
const unsigned char code F6x8[][6] =
{
0x00, 0x00, 0x00, 0x00, 0x00, 0x00,// sp
0x00, 0x00, 0x00, 0x2f, 0x00, 0x00,// !
0x00, 0x00, 0x07, 0x00, 0x07, 0x00,// "
0x00, 0x14, 0x7f, 0x14, 0x7f, 0x14,// #
0x00, 0x24, 0x2a, 0x7f, 0x2a, 0x12,// $
0x00, 0x62, 0x64, 0x08, 0x13, 0x23,// %
0x00, 0x36, 0x49, 0x55, 0x22, 0x50,// &
0x00, 0x00, 0x05, 0x03, 0x00, 0x00,// '
0x00, 0x00, 0x1c, 0x22, 0x41, 0x00,// (
0x00, 0x00, 0x41, 0x22, 0x1c, 0x00,// )
0x00, 0x14, 0x08, 0x3E, 0x08, 0x14,// *
0x00, 0x08, 0x08, 0x3E, 0x08, 0x08,// +
0x00, 0x00, 0x00, 0xA0, 0x60, 0x00,// ,
0x00, 0x08, 0x08, 0x08, 0x08, 0x08,// -
0x00, 0x00, 0x60, 0x60, 0x00, 0x00,// .
0x00, 0x20, 0x10, 0x08, 0x04, 0x02,// /
0x00, 0x3E, 0x51, 0x49, 0x45, 0x3E,// 0
0x00, 0x00, 0x42, 0x7F, 0x40, 0x00,// 1
0x00, 0x42, 0x61, 0x51, 0x49, 0x46,// 2
0x00, 0x21, 0x41, 0x45, 0x4B, 0x31,// 3
0x00, 0x18, 0x14, 0x12, 0x7F, 0x10,// 4
0x00, 0x27, 0x45, 0x45, 0x45, 0x39,// 5
0x00, 0x3C, 0x4A, 0x49, 0x49, 0x30,// 6
0x00, 0x01, 0x71, 0x09, 0x05, 0x03,// 7
0x00, 0x36, 0x49, 0x49, 0x49, 0x36,// 8
0x00, 0x06, 0x49, 0x49, 0x29, 0x1E,// 9
0x00, 0x00, 0x36, 0x36, 0x00, 0x00,// :
0x00, 0x00, 0x56, 0x36, 0x00, 0x00,// ;
0x00, 0x08, 0x14, 0x22, 0x41, 0x00,// <
0x00, 0x14, 0x14, 0x14, 0x14, 0x14,// =
0x00, 0x00, 0x41, 0x22, 0x14, 0x08,// >
0x00, 0x02, 0x01, 0x51, 0x09, 0x06,// ?
0x00, 0x32, 0x49, 0x59, 0x51, 0x3E,// @
0x00, 0x7C, 0x12, 0x11, 0x12, 0x7C,// A
0x00, 0x7F, 0x49, 0x49, 0x49, 0x36,// B
0x00, 0x3E, 0x41, 0x41, 0x41, 0x22,// C
0x00, 0x7F, 0x41, 0x41, 0x22, 0x1C,// D
0x00, 0x7F, 0x49, 0x49, 0x49, 0x41,// E
0x00, 0x7F, 0x09, 0x09, 0x09, 0x01,// F
0x00, 0x3E, 0x41, 0x49, 0x49, 0x7A,// G
0x00, 0x7F, 0x08, 0x08, 0x08, 0x7F,// H
0x00, 0x00, 0x41, 0x7F, 0x41, 0x00,// I
0x00, 0x20, 0x40, 0x41, 0x3F, 0x01,// J
0x00, 0x7F, 0x08, 0x14, 0x22, 0x41,// K
0x00, 0x7F, 0x40, 0x40, 0x40, 0x40,// L
0x00, 0x7F, 0x02, 0x0C, 0x02, 0x7F,// M
0x00, 0x7F, 0x04, 0x08, 0x10, 0x7F,// N
0x00, 0x3E, 0x41, 0x41, 0x41, 0x3E,// O
0x00, 0x7F, 0x09, 0x09, 0x09, 0x06,// P
0x00, 0x3E, 0x41, 0x51, 0x21, 0x5E,// Q
0x00, 0x7F, 0x09, 0x19, 0x29, 0x46,// R
0x00, 0x46, 0x49, 0x49, 0x49, 0x31,// S
0x00, 0x01, 0x01, 0x7F, 0x01, 0x01,// T
0x00, 0x3F, 0x40, 0x40, 0x40, 0x3F,// U
0x00, 0x1F, 0x20, 0x40, 0x20, 0x1F,// V
0x00, 0x3F, 0x40, 0x38, 0x40, 0x3F,// W
0x00, 0x63, 0x14, 0x08, 0x14, 0x63,// X
0x00, 0x07, 0x08, 0x70, 0x08, 0x07,// Y
0x00, 0x61, 0x51, 0x49, 0x45, 0x43,// Z
0x00, 0x00, 0x7F, 0x41, 0x41, 0x00,// [
0x00, 0x55, 0x2A, 0x55, 0x2A, 0x55,// 55
0x00, 0x00, 0x41, 0x41, 0x7F, 0x00,// ]
0x00, 0x04, 0x02, 0x01, 0x02, 0x04,// ^
0x00, 0x40, 0x40, 0x40, 0x40, 0x40,// _
0x00, 0x00, 0x01, 0x02, 0x04, 0x00,// '
0x00, 0x20, 0x54, 0x54, 0x54, 0x78,// a
0x00, 0x7F, 0x48, 0x44, 0x44, 0x38,// b
0x00, 0x38, 0x44, 0x44, 0x44, 0x20,// c
0x00, 0x38, 0x44, 0x44, 0x48, 0x7F,// d
0x00, 0x38, 0x54, 0x54, 0x54, 0x18,// e
0x00, 0x08, 0x7E, 0x09, 0x01, 0x02,// f
0x00, 0x18, 0xA4, 0xA4, 0xA4, 0x7C,// g
0x00, 0x7F, 0x08, 0x04, 0x04, 0x78,// h
0x00, 0x00, 0x44, 0x7D, 0x40, 0x00,// i
0x00, 0x40, 0x80, 0x84, 0x7D, 0x00,// j
0x00, 0x7F, 0x10, 0x28, 0x44, 0x00,// k
0x00, 0x00, 0x41, 0x7F, 0x40, 0x00,// l
0x00, 0x7C, 0x04, 0x18, 0x04, 0x78,// m
0x00, 0x7C, 0x08, 0x04, 0x04, 0x78,// n
0x00, 0x38, 0x44, 0x44, 0x44, 0x38,// o
0x00, 0xFC, 0x24, 0x24, 0x24, 0x18,// p
0x00, 0x18, 0x24, 0x24, 0x18, 0xFC,// q
0x00, 0x7C, 0x08, 0x04, 0x04, 0x08,// r
0x00, 0x48, 0x54, 0x54, 0x54, 0x20,// s
0x00, 0x04, 0x3F, 0x44, 0x40, 0x20,// t
0x00, 0x3C, 0x40, 0x40, 0x20, 0x7C,// u
0x00, 0x1C, 0x20, 0x40, 0x20, 0x1C,// v
0x00, 0x3C, 0x40, 0x30, 0x40, 0x3C,// w
0x00, 0x44, 0x28, 0x10, 0x28, 0x44,// x
0x00, 0x1C, 0xA0, 0xA0, 0xA0, 0x7C,// y
0x00, 0x44, 0x64, 0x54, 0x4C, 0x44,// z
0x14, 0x14, 0x14, 0x14, 0x14, 0x14,// horiz lines
};
/****************************************8*16的点阵************************************/
const unsigned char code F8X16[]=
{
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,// 0
0x00,0x00,0x00,0xF8,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x33,0x30,0x00,0x00,0x00,//! 1
0x00,0x10,0x0C,0x06,0x10,0x0C,0x06,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,//" 2
0x40,0xC0,0x78,0x40,0xC0,0x78,0x40,0x00,0x04,0x3F,0x04,0x04,0x3F,0x04,0x04,0x00,//# 3
0x00,0x70,0x88,0xFC,0x08,0x30,0x00,0x00,0x00,0x18,0x20,0xFF,0x21,0x1E,0x00,0x00,//$ 4
0xF0,0x08,0xF0,0x00,0xE0,0x18,0x00,0x00,0x00,0x21,0x1C,0x03,0x1E,0x21,0x1E,0x00,//% 5
0x00,0xF0,0x08,0x88,0x70,0x00,0x00,0x00,0x1E,0x21,0x23,0x24,0x19,0x27,0x21,0x10,//& 6
0x10,0x16,0x0E,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,//' 7
0x00,0x00,0x00,0xE0,0x18,0x04,0x02,0x00,0x00,0x00,0x00,0x07,0x18,0x20,0x40,0x00,//( 8
0x00,0x02,0x04,0x18,0xE0,0x00,0x00,0x00,0x00,0x40,0x20,0x18,0x07,0x00,0x00,0x00,//) 9
0x40,0x40,0x80,0xF0,0x80,0x40,0x40,0x00,0x02,0x02,0x01,0x0F,0x01,0x02,0x02,0x00,//* 10
0x00,0x00,0x00,0xF0,0x00,0x00,0x00,0x00,0x01,0x01,0x01,0x1F,0x01,0x01,0x01,0x00,//+ 11
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x80,0xB0,0x70,0x00,0x00,0x00,0x00,0x00,//, 12
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x01,0x01,0x01,0x01,0x01,0x01,//- 13
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x30,0x30,0x00,0x00,0x00,0x00,0x00,//. 14
0x00,0x00,0x00,0x00,0x80,0x60,0x18,0x04,0x00,0x60,0x18,0x06,0x01,0x00,0x00,0x00,/// 15
0x00,0xE0,0x10,0x08,0x08,0x10,0xE0,0x00,0x00,0x0F,0x10,0x20,0x20,0x10,0x0F,0x00,//0 16
0x00,0x10,0x10,0xF8,0x00,0x00,0x00,0x00,0x00,0x20,0x20,0x3F,0x20,0x20,0x00,0x00,//1 17
0x00,0x70,0x08,0x08,0x08,0x88,0x70,0x00,0x00,0x30,0x28,0x24,0x22,0x21,0x30,0x00,//2 18
0x00,0x30,0x08,0x88,0x88,0x48,0x30,0x00,0x00,0x18,0x20,0x20,0x20,0x11,0x0E,0x00,//3 19
0x00,0x00,0xC0,0x20,0x10,0xF8,0x00,0x00,0x00,0x07,0x04,0x24,0x24,0x3F,0x24,0x00,//4 20
0x00,0xF8,0x08,0x88,0x88,0x08,0x08,0x00,0x00,0x19,0x21,0x20,0x20,0x11,0x0E,0x00,//5 21
0x00,0xE0,0x10,0x88,0x88,0x18,0x00,0x00,0x00,0x0F,0x11,0x20,0x20,0x11,0x0E,0x00,//6 22
0x00,0x38,0x08,0x08,0xC8,0x38,0x08,0x00,0x00,0x00,0x00,0x3F,0x00,0x00,0x00,0x00,//7 23
0x00,0x70,0x88,0x08,0x08,0x88,0x70,0x00,0x00,0x1C,0x22,0x21,0x21,0x22,0x1C,0x00,//8 24
0x00,0xE0,0x10,0x08,0x08,0x10,0xE0,0x00,0x00,0x00,0x31,0x22,0x22,0x11,0x0F,0x00,//9 25
0x00,0x00,0x00,0xC0,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x30,0x30,0x00,0x00,0x00,//: 26
0x00,0x00,0x00,0x80,0x00,0x00,0x00,0x00,0x00,0x00,0x80,0x60,0x00,0x00,0x00,0x00,//; 27
0x00,0x00,0x80,0x40,0x20,0x10,0x08,0x00,0x00,0x01,0x02,0x04,0x08,0x10,0x20,0x00,//< 28
0x40,0x40,0x40,0x40,0x40,0x40,0x40,0x00,0x04,0x04,0x04,0x04,0x04,0x04,0x04,0x00,//= 29
0x00,0x08,0x10,0x20,0x40,0x80,0x00,0x00,0x00,0x20,0x10,0x08,0x04,0x02,0x01,0x00,//> 30
0x00,0x70,0x48,0x08,0x08,0x08,0xF0,0x00,0x00,0x00,0x00,0x30,0x36,0x01,0x00,0x00,//? 31
0xC0,0x30,0xC8,0x28,0xE8,0x10,0xE0,0x00,0x07,0x18,0x27,0x24,0x23,0x14,0x0B,0x00,//@ 32
0x00,0x00,0xC0,0x38,0xE0,0x00,0x00,0x00,0x20,0x3C,0x23,0x02,0x02,0x27,0x38,0x20,//A 33
0x08,0xF8,0x88,0x88,0x88,0x70,0x00,0x00,0x20,0x3F,0x20,0x20,0x20,0x11,0x0E,0x00,//B 34
0xC0,0x30,0x08,0x08,0x08,0x08,0x38,0x00,0x07,0x18,0x20,0x20,0x20,0x10,0x08,0x00,//C 35
0x08,0xF8,0x08,0x08,0x08,0x10,0xE0,0x00,0x20,0x3F,0x20,0x20,0x20,0x10,0x0F,0x00,//D 36
0x08,0xF8,0x88,0x88,0xE8,0x08,0x10,0x00,0x20,0x3F,0x20,0x20,0x23,0x20,0x18,0x00,//E 37
0x08,0xF8,0x88,0x88,0xE8,0x08,0x10,0x00,0x20,0x3F,0x20,0x00,0x03,0x00,0x00,0x00,//F 38
0xC0,0x30,0x08,0x08,0x08,0x38,0x00,0x00,0x07,0x18,0x20,0x20,0x22,0x1E,0x02,0x00,//G 39
0x08,0xF8,0x08,0x00,0x00,0x08,0xF8,0x08,0x20,0x3F,0x21,0x01,0x01,0x21,0x3F,0x20,//H 40
0x00,0x08,0x08,0xF8,0x08,0x08,0x00,0x00,0x00,0x20,0x20,0x3F,0x20,0x20,0x00,0x00,//I 41
0x00,0x00,0x08,0x08,0xF8,0x08,0x08,0x00,0xC0,0x80,0x80,0x80,0x7F,0x00,0x00,0x00,//J 42
0x08,0xF8,0x88,0xC0,0x28,0x18,0x08,0x00,0x20,0x3F,0x20,0x01,0x26,0x38,0x20,0x00,//K 43
0x08,0xF8,0x08,0x00,0x00,0x00,0x00,0x00,0x20,0x3F,0x20,0x20,0x20,0x20,0x30,0x00,//L 44
0x08,0xF8,0xF8,0x00,0xF8,0xF8,0x08,0x00,0x20,0x3F,0x00,0x3F,0x00,0x3F,0x20,0x00,//M 45
0x08,0xF8,0x30,0xC0,0x00,0x08,0xF8,0x08,0x20,0x3F,0x20,0x00,0x07,0x18,0x3F,0x00,//N 46
0xE0,0x10,0x08,0x08,0x08,0x10,0xE0,0x00,0x0F,0x10,0x20,0x20,0x20,0x10,0x0F,0x00,//O 47
0x08,0xF8,0x08,0x08,0x08,0x08,0xF0,0x00,0x20,0x3F,0x21,0x01,0x01,0x01,0x00,0x00,//P 48
0xE0,0x10,0x08,0x08,0x08,0x10,0xE0,0x00,0x0F,0x18,0x24,0x24,0x38,0x50,0x4F,0x00,//Q 49
0x08,0xF8,0x88,0x88,0x88,0x88,0x70,0x00,0x20,0x3F,0x20,0x00,0x03,0x0C,0x30,0x20,//R 50
0x00,0x70,0x88,0x08,0x08,0x08,0x38,0x00,0x00,0x38,0x20,0x21,0x21,0x22,0x1C,0x00,//S 51
0x18,0x08,0x08,0xF8,0x08,0x08,0x18,0x00,0x00,0x00,0x20,0x3F,0x20,0x00,0x00,0x00,//T 52
0x08,0xF8,0x08,0x00,0x00,0x08,0xF8,0x08,0x00,0x1F,0x20,0x20,0x20,0x20,0x1F,0x00,//U 53
0x08,0x78,0x88,0x00,0x00,0xC8,0x38,0x08,0x00,0x00,0x07,0x38,0x0E,0x01,0x00,0x00,//V 54
0xF8,0x08,0x00,0xF8,0x00,0x08,0xF8,0x00,0x03,0x3C,0x07,0x00,0x07,0x3C,0x03,0x00,//W 55
0x08,0x18,0x68,0x80,0x80,0x68,0x18,0x08,0x20,0x30,0x2C,0x03,0x03,0x2C,0x30,0x20,//X 56
0x08,0x38,0xC8,0x00,0xC8,0x38,0x08,0x00,0x00,0x00,0x20,0x3F,0x20,0x00,0x00,0x00,//Y 57
0x10,0x08,0x08,0x08,0xC8,0x38,0x08,0x00,0x20,0x38,0x26,0x21,0x20,0x20,0x18,0x00,//Z 58
0x00,0x00,0x00,0xFE,0x02,0x02,0x02,0x00,0x00,0x00,0x00,0x7F,0x40,0x40,0x40,0x00,//[ 59
0x00,0x0C,0x30,0xC0,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x06,0x38,0xC0,0x00,//\ 60
0x00,0x02,0x02,0x02,0xFE,0x00,0x00,0x00,0x00,0x40,0x40,0x40,0x7F,0x00,0x00,0x00,//] 61
0x00,0x00,0x04,0x02,0x02,0x02,0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,//^ 62
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,//_ 63
0x00,0x02,0x02,0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,//` 64
0x00,0x00,0x80,0x80,0x80,0x80,0x00,0x00,0x00,0x19,0x24,0x22,0x22,0x22,0x3F,0x20,//a 65
0x08,0xF8,0x00,0x80,0x80,0x00,0x00,0x00,0x00,0x3F,0x11,0x20,0x20,0x11,0x0E,0x00,//b 66
0x00,0x00,0x00,0x80,0x80,0x80,0x00,0x00,0x00,0x0E,0x11,0x20,0x20,0x20,0x11,0x00,//c 67
0x00,0x00,0x00,0x80,0x80,0x88,0xF8,0x00,0x00,0x0E,0x11,0x20,0x20,0x10,0x3F,0x20,//d 68
0x00,0x00,0x80,0x80,0x80,0x80,0x00,0x00,0x00,0x1F,0x22,0x22,0x22,0x22,0x13,0x00,//e 69
0x00,0x80,0x80,0xF0,0x88,0x88,0x88,0x18,0x00,0x20,0x20,0x3F,0x20,0x20,0x00,0x00,//f 70
0x00,0x00,0x80,0x80,0x80,0x80,0x80,0x00,0x00,0x6B,0x94,0x94,0x94,0x93,0x60,0x00,//g 71
0x08,0xF8,0x00,0x80,0x80,0x80,0x00,0x00,0x20,0x3F,0x21,0x00,0x00,0x20,0x3F,0x20,//h 72
0x00,0x80,0x98,0x98,0x00,0x00,0x00,0x00,0x00,0x20,0x20,0x3F,0x20,0x20,0x00,0x00,//i 73
0x00,0x00,0x00,0x80,0x98,0x98,0x00,0x00,0x00,0xC0,0x80,0x80,0x80,0x7F,0x00,0x00,//j 74
0x08,0xF8,0x00,0x00,0x80,0x80,0x80,0x00,0x20,0x3F,0x24,0x02,0x2D,0x30,0x20,0x00,//k 75
0x00,0x08,0x08,0xF8,0x00,0x00,0x00,0x00,0x00,0x20,0x20,0x3F,0x20,0x20,0x00,0x00,//l 76
0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x00,0x20,0x3F,0x20,0x00,0x3F,0x20,0x00,0x3F,//m 77
0x80,0x80,0x00,0x80,0x80,0x80,0x00,0x00,0x20,0x3F,0x21,0x00,0x00,0x20,0x3F,0x20,//n 78
0x00,0x00,0x80,0x80,0x80,0x80,0x00,0x00,0x00,0x1F,0x20,0x20,0x20,0x20,0x1F,0x00,//o 79
0x80,0x80,0x00,0x80,0x80,0x00,0x00,0x00,0x80,0xFF,0xA1,0x20,0x20,0x11,0x0E,0x00,//p 80
0x00,0x00,0x00,0x80,0x80,0x80,0x80,0x00,0x00,0x0E,0x11,0x20,0x20,0xA0,0xFF,0x80,//q 81
0x80,0x80,0x80,0x00,0x80,0x80,0x80,0x00,0x20,0x20,0x3F,0x21,0x20,0x00,0x01,0x00,//r 82
0x00,0x00,0x80,0x80,0x80,0x80,0x80,0x00,0x00,0x33,0x24,0x24,0x24,0x24,0x19,0x00,//s 83
0x00,0x80,0x80,0xE0,0x80,0x80,0x00,0x00,0x00,0x00,0x00,0x1F,0x20,0x20,0x00,0x00,//t 84
0x80,0x80,0x00,0x00,0x00,0x80,0x80,0x00,0x00,0x1F,0x20,0x20,0x20,0x10,0x3F,0x20,//u 85
0x80,0x80,0x80,0x00,0x00,0x80,0x80,0x80,0x00,0x01,0x0E,0x30,0x08,0x06,0x01,0x00,//v 86
0x80,0x80,0x00,0x80,0x00,0x80,0x80,0x80,0x0F,0x30,0x0C,0x03,0x0C,0x30,0x0F,0x00,//w 87
0x00,0x80,0x80,0x00,0x80,0x80,0x80,0x00,0x00,0x20,0x31,0x2E,0x0E,0x31,0x20,0x00,//x 88
0x80,0x80,0x80,0x00,0x00,0x80,0x80,0x80,0x80,0x81,0x8E,0x70,0x18,0x06,0x01,0x00,//y 89
0x00,0x80,0x80,0x80,0x80,0x80,0x80,0x00,0x00,0x21,0x30,0x2C,0x22,0x21,0x30,0x00,//z 90
0x00,0x00,0x00,0x00,0x80,0x7C,0x02,0x02,0x00,0x00,0x00,0x00,0x00,0x3F,0x40,0x40,//{ 91
0x00,0x00,0x00,0x00,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xFF,0x00,0x00,0x00,//| 92
0x00,0x02,0x02,0x7C,0x80,0x00,0x00,0x00,0x00,0x40,0x40,0x3F,0x00,0x00,0x00,0x00,//} 93
0x00,0x06,0x01,0x01,0x02,0x02,0x04,0x04,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,//~ 94
};
unsigned char code Hzk[][32]={
//{0x00,0x00,0xF0,0x10,0x10,0x10,0x10,0xFF,0x10,0x10,0x10,0x10,0xF0,0x00,0x00,0x00},
//{0x00,0x00,0x0F,0x04,0x04,0x04,0x04,0xFF,0x04,0x04,0x04,0x04,0x0F,0x00,0x00,0x00},/*"中",0*/
//{0x40,0x40,0x40,0x5F,0x55,0x55,0x55,0x75,0x55,0x55,0x55,0x5F,0x40,0x40,0x40,0x00},
//{0x00,0x40,0x20,0x0F,0x09,0x49,0x89,0x79,0x09,0x09,0x09,0x0F,0x20,0x40,0x00,0x00},/*"景",1*/
//{0x00,0xFE,0x02,0x42,0x4A,0xCA,0x4A,0x4A,0xCA,0x4A,0x4A,0x42,0x02,0xFE,0x00,0x00},
//{0x00,0xFF,0x40,0x50,0x4C,0x43,0x40,0x40,0x4F,0x50,0x50,0x5C,0x40,0xFF,0x00,0x00},/*"园",2*/
//{0x00,0x00,0xF8,0x88,0x88,0x88,0x88,0xFF,0x88,0x88,0x88,0x88,0xF8,0x00,0x00,0x00},
//{0x00,0x00,0x1F,0x08,0x08,0x08,0x08,0x7F,0x88,0x88,0x88,0x88,0x9F,0x80,0xF0,0x00},/*"电",3*/
//{0x80,0x82,0x82,0x82,0x82,0x82,0x82,0xE2,0xA2,0x92,0x8A,0x86,0x82,0x80,0x80,0x00},
//{0x00,0x00,0x00,0x00,0x00,0x40,0x80,0x7F,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},/*"子",4*/
//{0x24,0x24,0xA4,0xFE,0xA3,0x22,0x00,0x22,0xCC,0x00,0x00,0xFF,0x00,0x00,0x00,0x00},
//{0x08,0x06,0x01,0xFF,0x00,0x01,0x04,0x04,0x04,0x04,0x04,0xFF,0x02,0x02,0x02,0x00},/*"科",5*/
//{0x10,0x10,0x10,0xFF,0x10,0x90,0x08,0x88,0x88,0x88,0xFF,0x88,0x88,0x88,0x08,0x00},
//{0x04,0x44,0x82,0x7F,0x01,0x80,0x80,0x40,0x43,0x2C,0x10,0x28,0x46,0x81,0x80,0x00},/*"技",6*/
// 长(0) 春(1) 理(2) 工(3) 大(4) 学(5) 好(6) 好(7) 学(8) 习(9)
{0x80,0x80,0x80,0x80,0xFF,0x80,0x80,0xA0,0x90,0x88,0x84,0x82,0x80,0x80,0x80,0x00},
{0x00,0x00,0x00,0x00,0xFF,0x40,0x21,0x12,0x04,0x08,0x10,0x20,0x20,0x40,0x40,0x00},/*"长",0*/
/* (16 X 16 , 宋体 )*/
{0x40,0x44,0x54,0x54,0xD4,0x54,0x74,0x5F,0x54,0x54,0xD4,0x54,0x54,0x44,0x40,0x00},
{0x04,0x04,0x02,0x01,0xFE,0x92,0x92,0x92,0x92,0x92,0xFE,0x01,0x02,0x04,0x04,0x00},/*"春",1*/
/* (16 X 16 , 宋体 )*/
{0x04,0x84,0x84,0xFC,0x84,0x84,0x00,0xFE,0x92,0x92,0xFE,0x92,0x92,0xFE,0x00,0x00},
{0x20,0x60,0x20,0x1F,0x10,0x10,0x40,0x44,0x44,0x44,0x7F,0x44,0x44,0x44,0x40,0x00},/*"理",2*/
/* (16 X 16 , 宋体 )*/
{0x00,0x04,0x04,0x04,0x04,0x04,0x04,0xFC,0x04,0x04,0x04,0x04,0x04,0x04,0x00,0x00},
{0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x3F,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x00},/*"工",3*/
/* (16 X 16 , 宋体 )*/
{0x20,0x20,0x20,0x20,0x20,0x20,0x20,0xFF,0x20,0x20,0x20,0x20,0x20,0x20,0x20,0x00},
{0x80,0x80,0x40,0x20,0x10,0x0C,0x03,0x00,0x03,0x0C,0x10,0x20,0x40,0x80,0x80,0x00},/*"大",4*/
/* (16 X 16 , 宋体 )*/
{0x40,0x30,0x11,0x96,0x90,0x90,0x91,0x96,0x90,0x90,0x98,0x14,0x13,0x50,0x30,0x00},
{0x04,0x04,0x04,0x04,0x04,0x44,0x84,0x7E,0x06,0x05,0x04,0x04,0x04,0x04,0x04,0x00},/*"学",5*/
/* (16 X 16 , 宋体 )*/
{0x10,0x10,0xF0,0x1F,0x10,0xF0,0x00,0x80,0x82,0x82,0xE2,0x92,0x8A,0x86,0x80,0x00},
{0x40,0x22,0x15,0x08,0x16,0x61,0x00,0x00,0x40,0x80,0x7F,0x00,0x00,0x00,0x00,0x00},/*"好",6*/
/* (16 X 16 , 宋体 )*/
{0x10,0x10,0xF0,0x1F,0x10,0xF0,0x00,0x80,0x82,0x82,0xE2,0x92,0x8A,0x86,0x80,0x00},
{0x40,0x22,0x15,0x08,0x16,0x61,0x00,0x00,0x40,0x80,0x7F,0x00,0x00,0x00,0x00,0x00},/*"好",7*/
/* (16 X 16 , 宋体 )*/
{0x40,0x30,0x11,0x96,0x90,0x90,0x91,0x96,0x90,0x90,0x98,0x14,0x13,0x50,0x30,0x00},
{0x04,0x04,0x04,0x04,0x04,0x44,0x84,0x7E,0x06,0x05,0x04,0x04,0x04,0x04,0x04,0x00},/*"学",8*/
/* (16 X 16 , 宋体 )*/
{0x00,0x02,0x02,0x02,0x12,0x22,0xC2,0x02,0x02,0x02,0x02,0x02,0xFE,0x00,0x00,0x00},
{0x00,0x08,0x18,0x08,0x04,0x04,0x04,0x02,0x02,0x41,0x81,0x40,0x3F,0x00,0x00,0x00},/*"习",9*/
/* (16 X 16 , 宋体 )*/
};
#endif
/* ==================== Uart\uart.c ==================== */
#include "uart.h"
#include "main.h"
//串口发送一个字节
void UART_Send_Byte(uchar send_byte)
{
SBUF = send_byte;
while(!TI);
TI=0;
}
//串口发送字符串
void UART_Send_Str(uchar *send_str)
{
while(*send_str != '\0') //判断字符串结束符，如果识别到‘\0',则跳出while，结束发送
{
UART_Send_Byte(*send_str++); //本质是一个字节一个字节的发送，
//发送完一个字节，地址+1，等待发送下一个字节，直到检测到字符串结束符为止
}
}
void UART_Init(void)
{
SCON = 0x50; //串口配成工作方式1
PCON &= 0x7F; //波特率不加倍
TMOD &= 0x0f;
TMOD |= 0x20; //定时器1，模式二，自动重装初值，串口按照一定速率发数据，需要用的定时器
TH1 = 0xFD;
TL1 = 0xFD; //@11.0592MH时钟，9600比特率定时器初值
TR1 = 1; //定时器开始运行
ES = 1; //串口中断打开
EA=1; //总中断打开
recv = 0;
}
/* ==================== Uart\uart.h ==================== */
#ifndef _UART_H_
#define _UART_H_
#include "main.h"
void UART_Send_Byte(uchar send_byte);
void UART_Send_Str(uchar *send_str);
void UART_Init(void);
#endif
一、IIC具体应用过程
前几节实现了 START、发送字节、接收 ACK 和 STOP。本节要回答更高一层的问题：第一个字节为什么是 0x78，第二个字节为什么有时是 0x00、有时是 0x40，第三个字节又代表什么。
1.1 IIC应用
I²C 总线层只认识地址、方向、字节和应答；SSD1306 器件层再解释控制字节、命令与显存数据。一次 OLED 写操作需要同时满足这两层协议。
1.1.1 IIC总线设备通信过程
主机发出 START 后，第一字节不是普通有效数据，而是“7 位从机地址 + 1 位读写方向”：
bit7 bit6 bit5 bit4 bit3 bit2 bit1 bit0
A6 A5 A4 A3 A2 A1 A0 R/W
└────────7位从机地址────────┘ └方向位
0=写
1=读
这是地址字节。主机仍按 8 位字节把它发到 SDA，但描述器件地址时通常只写 7 位值。地址匹配的从机在第 9 个时钟拉低 SDA 返回 ACK，其他从机保持释放状态。
典型写事务：
S → [7位地址 + W] → ACK → [数据1] → ACK → [数据2] → ACK → P
典型读事务：
S → [7位地址 + R] → ACK → [从机数据1] → 主机ACK
[从机数据2] → 主机NACK → P
其中 S 是 START，P 是 STOP。读最后一字节后，主机通常回 NACK 表示结束，再发 STOP。
1.1.2 代码分析
SSD1306 常用 7 位地址是 0x3C。代码发送的 0x78 是加入写方向后的地址字节：
[ 0x3C = 0b0111100 ]
[ (0x3C \ll 1) | 0 = 0b01111000 = 0x78 ]
拆位如下：
0x78 = 0 1 1 1 1 0 0 0
└────0x3C────┘ └W
A6..........A0 0
所以以下三种说法需要区分：
- SSD1306 的 7 位地址：0x3C；
- SSD1306 的 写地址字节：0x78；
- 若使用以 7 位地址为参数的 MCU 驱动库：传 0x3C，库内部再拼接方向位。
代码从 OLED_Init() 进入 OLED_WR_Byte()，再按命令/数据分支进入 Write_IIC_Command() 或 Write_IIC_Data()，最后才调用 IIC_Send_Byte() 逐位发送。
1.1.3 MCU_IIC接口
SSD1306 写命令的三字节含义：
START
0x78 → 地址字节：选择7位地址0x3C，并声明主机写
ACK
0x00 → SSD1306控制字节：后续内容作为命令
ACK
0xAE → SSD1306命令：Display OFF
ACK
STOP
写 GDDRAM 数据时：
START
0x78 → 地址+写
ACK
0x40 → SSD1306控制字节：后续内容作为显示数据
ACK
data → 8个像素对应的显存字节
ACK
STOP
0xAE 是“关闭显示输出”，不是清屏命令。OLED_Clear() 是循环写 1024 个 0 到 GDDRAM；二者作用不同。
控制字节的关键位是 Co 与 D/C#：
bit7 bit6 bit5..0
Co D/C# 0
0 0 0 → 0x00，后续按命令解释
0 1 0 → 0x40，后续按显示数据解释
配套代码每发送一个命令或数据都重新 START/STOP，逻辑直观但效率较低。SSD1306 支持在适当控制字节和寻址方式下连续发送多个字节，工程化驱动可减少地址与起停开销。
1.1.4 IIC总线设备相关
“7 位地址所以最多挂 2^7-1=127 个设备”并不准确。7 位共有 128 种组合，但 I²C 规范保留了 0000xxx 和 1111xxx 等地址用途，常规 7 位从机地址范围通常为 0x08～0x77，即理论上 112 个普通地址；实际数量还受以下条件限制：
- 模块地址是否可配置，不能有冲突；
- 总线电容、线长和上拉能力；
- 每个器件支持的最高速率与电平；
- 主机驱动的地址管理；
- 供电、电流和连接器资源。
VPU
│ │
RpSCL RpSDA
│ │
主机 ─────────── SCL/SDA总线 ─────────── 从机0x3C
├────────────── 从机0x50
└────────────── 从机0x68
同一地址出现两个从机时，写入相同数据可能让二者同时响应；读取时多个从机可能同时驱动 SDA，数据不可可靠区分。应修改地址引脚、使用 I²C 多路复用器或分到不同总线。
主机/从机更准确的现代术语也常写为 controller/target。角色描述的是谁发起并控制当前传输，不等同于 CPU 性能强弱。
三类事务的数据方向如下：
纯写：
主机 START → 地址+W → 寄存器/控制字节 → 数据 → STOP
纯读：
主机 START → 地址+R → 从机数据 → 主机NACK → STOP
常见“先写寄存器地址再读”：
主机 START → 地址+W → 寄存器号
→ Repeated START → 地址+R → 从机数据 → 主机NACK → STOP
重复起始 Repeated START 不先释放总线，常用于传感器和 EEPROM 的组合读。ACK 的归属应按“谁接收当前字节”判断：地址和主机写数据后的 ACK 通常由从机产生；主机读数据后的 ACK/NACK 由主机产生。课程图中的颜色只是图例，不能作为通用协议定义。