1. 综述

本例子应用 N32G45XVL-STB 开发板I2C 接口驱动OLED

2. 实现过程

2.1 硬件接口

OLED屏幕和N32G45x对应接口如下：

OLED屏幕只需要4根线和开发板连接起来

2.2 firmware 实现

2.2.1 I2C 接口实现

本程序采用模拟IO方法实现I2c接口，具体实现代码参考程序库
共享一个简单的I2C驱动-OpenEdv-开源电子网

在作者的gitee 的代码库也实现该功能：
源代码和开发文档地址：
https://gitee.com/mftang/n32-g45-xvl-stb.git

2.2.2 OLED 接口实现

/** \file

$Id: oled.c 40486 2018-08-12 13:50:21Z tangmingfei2013@126.com $

Copyright (c)tangmingfei2013@126.com Holding B.V.
All Rights Reserved.

This source code and any compilation or derivative thereof is the proprietary
information of mingfei.tang Holding B.V. and is confidential in nature.
Under no circumstances is this software to be combined with any
Open Source Software in any way or placed under an Open Source License
of any type without the express written permission of mingfei.tang Holding B.V.
*/
/*******************************************************************************
* EXPORT INCLUDE FILES
*******************************************************************************/
#include "I2C.h"
#include "oled.h"
/*******************************************************************************
* LOCAL INCLUDE FILES
*******************************************************************************/
#include "font.h"

static uint8_t charSize;
/******************************************************************************
* LOCAL FUNCTION DECLARATIONS
******************************************************************************/
static void oled_WriteRegister(uint8_t val,  uint8_t reg);

/******************************************************************************
* EXPORTED FUNCTIONS
******************************************************************************/
void oled_Init(void)
{ 
    i2c_Init();
    
    oled_WriteRegister(0xAE,PARA);//--display off
    oled_WriteRegister(0x00,PARA);//---set low column address
    oled_WriteRegister(0x10,PARA);//---set high column address
    oled_WriteRegister(0x40,PARA);//--set start line address  
    oled_WriteRegister(0xB0,PARA);//--set page address
    oled_WriteRegister(0x81,PARA); // contract control
    oled_WriteRegister(0xFF,PARA);//--128   
    oled_WriteRegister(0xA1,PARA);//set segment remap 
    oled_WriteRegister(0xA6,PARA);//--normal / reverse
    oled_WriteRegister(0xA8,PARA);//--set multiplex ratio(1 to 64)
    oled_WriteRegister(0x3F,PARA);//--1/32 duty
    oled_WriteRegister(0xC8,PARA);//Com scan direction
    oled_WriteRegister(0xD3,PARA);//-set display offset
    oled_WriteRegister(0x00,PARA);//

    oled_WriteRegister(0xD5,PARA);//set osc division
    oled_WriteRegister(0x80,PARA);//

    oled_WriteRegister(0xD8,PARA);//set area color mode off
    oled_WriteRegister(0x05,PARA);//

    oled_WriteRegister(0xD9,PARA);//Set Pre-Charge Period
    oled_WriteRegister(0xF1,PARA);//

    oled_WriteRegister(0xDA,PARA);//set com pin configuartion
    oled_WriteRegister(0x12,PARA);//

    oled_WriteRegister(0xDB,PARA);//set Vcomh
    oled_WriteRegister(0x30,PARA);//

    oled_WriteRegister(0x8D,PARA);//set charge pump enable
    oled_WriteRegister(0x14,PARA);//

    oled_WriteRegister(0xAF,PARA);//--turn on oled panel
    
    oled_Clear();

#if OLED_DEBUG  
    oled_SetCharSize( FONT_16 );  
    oled_PrintfString(6,0,(uint8_t*)"0.96' OLED TEST");  
    
    oled_SetCharSize( FONT_12 );
    oled_PrintfString(0,6,(uint8_t*)"ASCII:");  
    oled_PrintfString(60,6,(uint8_t*)"-CODE:");
#endif
    
} 

void oled_SetCharSize( uint8_t val )
{
   charSize = val;
}

void oled_SetPostion( uint8_t x, uint8_t y) 
{
    oled_WriteRegister(0xb0+y,PARA);
    oled_WriteRegister(((x&0xf0)>>4)|0x10,PARA);
    oled_WriteRegister((x&0x0f),PARA); 
}
 
void oled_displayOn(void)
{
    oled_WriteRegister(0X8D,PARA); 
    oled_WriteRegister(0X14,PARA); 
    oled_WriteRegister(0XAF,PARA);
}
  
void oled_DisplayOff(void)
{
    oled_WriteRegister(0X8D,PARA);
    oled_WriteRegister(0X10,PARA);
    oled_WriteRegister(0XAE,PARA);
}

void oled_Clear(void)  
{  
  uint8_t i,n;
  
  for(i=0;i<8;i++)  
  {  
      oled_WriteRegister (0xb0+i,PARA);   
      oled_WriteRegister (0x00,PARA);
      oled_WriteRegister (0x10,PARA); 
      
      for( n = 0;n < 128; n++)
      {
          oled_WriteRegister(0,DATA);
      } 
  } 
}

void oled_UpScreenOn(void)  
{  
    uint8_t i,n;
    
    for(i=0;i<8;i++)  
    {  
        oled_WriteRegister (0xb0+i,PARA);
        oled_WriteRegister (0x00,PARA); 
        oled_WriteRegister (0x10,PARA);
        
        for(n=0;n<128;n++)
        {
            oled_WriteRegister(1,DATA); 
        }
    } 
}

void oled_PrintfChar(uint8_t x,uint8_t y,uint8_t val )
{      	
    uint8_t character = 0;
    uint8_t i=0;
    
    character = val-' ';
    if( x > X_WIDTH-1)
    {
      x = 0;
      y += 2;
    }
    
    if( charSize == FONT_16 )
    {
          oled_SetPostion(x,y);	
          for( i = 0; i < 8; i++)
          {
              oled_WriteRegister(F8X16[character*16+i],DATA);
          }
          
          oled_SetPostion(x,y+1);
          for(i=0;i<8;i++)
          {
              oled_WriteRegister(F8X16[character*16+i+8],DATA);
          }
     }
    else 
    {
        oled_SetPostion(x,y);
        for(i=0;i<6;i++)
        {
            oled_WriteRegister(F6x8[character][i],DATA);
        }
    }
}

void oled_PrintfString(uint8_t x,uint8_t y,uint8_t *str  )
{
    uint8_t index = 0;
    
    while ( str[index]!='\0' )
    {
        oled_PrintfChar(x,y,str[index] );
       
        x += 8;
        if( x > 120 )
        {  
            x=0;
            y+=2;
        }
        index++;
    }
}

void oled_PrintmutiChar(uint8_t x,uint8_t y,uint8_t *str,  uint8_t length )
{
    for(uint8_t index = 0; index < length; index++ )
    {
        oled_PrintfChar(x,y,str[index] );
       
        x += 8;
        if( x > 120 )
        {  
            x=0;
            y+=2;
        }
    }
}

/******************************************************************************
* LOCAL FUNCTIONS
******************************************************************************/
static void oled_WriteRegister(uint8_t val,  uint8_t reg)
{  
    i2c_Start();
    
    i2c_SendByte( OLED_ADDRESS );   //Slave address,SA0=0   
    i2c_WaitAck();
    
    i2c_SendByte( reg );            //write register 
    i2c_WaitAck();
    
    i2c_SendByte( val );    
    i2c_WaitAck();
    
    i2c_Stop();    
}
/* End of this file */

3. 实现一个测试demo

3.1 需求：

采集SHT20温湿度数据，然后显示在OLED屏幕上

3.2 代码实现

以下只展示核心代码，详细实现过程，参考gitee 上项目库代码

void ui_init( void )
{
    oled_SetCharSize( FONT_12 );
    oled_PrintfString(OFFSET,2,(uint8_t*)"TM(C): ");

    oled_SetCharSize( FONT_12 );
    oled_PrintfString(OFFSET,6,(uint8_t*)"HM(%): ");
}

void ui_displayTempHumidy( void )
{
    uint8_t dataBuff[5];
    int32_t _outVal;
    
    shtOpt *shtOpt = sht2xdrv_getResult();
    
    // tempeture
    if(shtOpt->st_Temp.dataValid)
    {   
        _outVal = shtOpt->st_Temp.outValue;
        
        memset((char*)dataBuff, ' ', sizeof(dataBuff));
        ui_convert(_outVal, dataBuff);
        
        oled_SetCharSize( FONT_16 );
        oled_PrintmutiChar(50+OFFSET,2,(uint8_t*)dataBuff, sizeof(dataBuff));
        shtOpt->st_Temp.dataValid = 0;
    }
    
    // humidity
    if(shtOpt->st_RH.dataValid)
    {   
        _outVal = shtOpt->st_RH.outValue;
        
        memset((char*)dataBuff, ' ', sizeof(dataBuff));
        ui_convert(_outVal, dataBuff);
        
        oled_SetCharSize( FONT_16 );
        oled_PrintmutiChar(50+OFFSET,6,(uint8_t*)dataBuff, sizeof(dataBuff));
        shtOpt->st_RH.dataValid = 0;
    }
}


void main_ui( void )
{
    ui_displayTempHumidy();
}

static void ui_convert( int32_t inputVal, uint8_t *dataBuff )
{
    int8_t temp;
    
    dataBuff[0] = inputVal/1000 + 0x30;
    dataBuff[1] = (inputVal%1000)/100 + 0x30;
    
    dataBuff[2] = '.';
    
    temp = (inputVal%1000)%100;
    
    dataBuff[3] = temp/10 + 0x30 ;
    dataBuff[4] = temp%10 + 0x30;
}

4 测试