0.96 inch IIC LCD driver based on stc8g1k08

STC8G A series of MCU is integrated inside I2C Serial controller .

STC8G Series of I2C The bus provides two modes of operation ： Host mode （SCL For the output port , Send synchronous clock signal ）; Slave mode （SCL For the input port , Receive synchronous clock signal ）.

I2C Related registers ：

I2C Host mode related registers ：

I2CCFG： Configuration register , Bus speed control

Symbol	describe	Address	B7	B6	B5	B4	B3	B2	B1	B0
I2CCFG	Configuration register	FE80H	ENI2C	MSSL	MSSPEED[5:0]

ENI2C：I2C Function enable control bit

0： prohibit I2C function

1： allow I2C function

MSSL：I2C Operating mode selection bit

0： Slave mode

1： Host mode

MSSPEED[5:0]：I2C Bus speed control

I2C Bus speed =FOSC/2/(MSSPEEED*2+4)

Be careful ： Only when I2C When the module is in host mode ,MSSPEED The waiting parameter of parameter setting is valid . This parameter is mainly used for I2C Setting of start signal and stop signal establishment and holding time .

I2CMSCR： Host control register

Symbol	describe	Address	B7	B6	B5	B4	B3	B2	B1	B0
I2CMSCR	Host control register	FE81H	EMSI	-	-	-	MSCMD[3:0]

EMSI： Host mode interrupt enable control bit

0： Turn off the interrupt of host mode

1： Turn on the interrupt of host mode

MSCMD[3:0]： Host command

0000： standby , No action

0001： Start instruction , Send the start signal .

0010： Send data instructions

0011： receive ACK command

0100： Receive data command

0101： send out ACK command

0110： Stop the order , Send stop signal .

1001： Start command + Send data command + receive ACK command

1010： Send data command + receive ACK command

1011： Receive data command and send ACK command

1100： Receive data command + send out NAK command

I2CMSAUX： Host auxiliary control register

Symbol	describe	Address	B7	B6	B5	B4	B3	B2	B1	B0
I2CMSAUX	Host auxiliary control register	FE88H	-	-	-	-	-	-	-	WDTA

WDTA： Host mode ,I2C Data automatic transmission permission bit .

I2CMSST： Host status register

Symbol	describe	Address	B7	B6	B5	B4	B3	B2	B1	B0
I2CMSST	Host status register	FE82H	MSBUSY	MSIF	-	-	-	-	MSACKI	MSACKO

MSBUSY： Host mode I2C Control status bit

MSIF： Interrupt request bit in host mode

MSACKI： In host mode , send out 0011 Order to I2CMSCR Of MSMD Received after bit ACK data .

MSACKO： In host mode , Prepare to send ACK The signal .

I2C Slave mode related registers ：

I2CSLCR： Control register

Symbol	describe	Address	B7	B6	B5	B4	B3	B2	B1	B0
I2CSLCR	Slave control register	FE83H	-	ESTAI	ERXI	ETXI	ESTOI	-	-	SLRST

ESTAI： Slave mode reception START Signal interrupt enable bit

ERXI： Interrupt allowed bit after receiving a byte in slave mode

ETXI： Interrupt allowed bit after sending a byte in slave mode

ESTOI： Receive in slave mode STOP Interrupt allowable bit of signal

SLRST： Reset slave mode

I2CSLST： Status register

Symbol	describe	Address	B7	B6	B5	B4	B3	B2	B1	B0
I2CSLST	Status register	FE84H	SLBUSY	STAIF	RXIF	TXIF	STOIF	-	SLACKI	SLACKO

SLBUSY：I2C Controller status bit , Idle and busy

STAIF： Slave mode received START Interrupt request bit after signal

RXIF： Received in slave mode 1 Interrupt request bit after byte data .

TXIF： Interrupt request bit after sending one byte of data in slave mode .

STOIF： Slave mode received STOP Interrupt request bit after signal .

SLACKI： In slave mode , The received ACK data .

SLACKO： In slave mode , Prepare to send ACK The signal .

I2CSLADR： Address register

Symbol	describe	Address	B7	B6	B5	B4	B3	B2	B1	B0
I2CSLADR	Slave address register	FE85H	IACSLADR[7:1]							MA

IACSLADR[7:1]: Slave device address

MA: Slave device address comparison control

0： The device address must be the same as I2CSLADR[7:1] identical

1： Ignore I2CSLADR[7:1] Settings in , Receive all device addresses

I2C Data register

I2CTXD： Send data register

Symbol	describe	Address	B7	B6	B5	B4	B3	B2	B1	B0
I2CTXD	Send data register	FE86H

I2CRXD： Receive data register

Symbol	describe	Address	B7	B6	B5	B4	B3	B2	B1	B0
I2CRXD	Receive data register	FE87H

Step by step routines ：

The LCD screen is ：0.96 " IIC The screen

// Hardware IIC initialization

void iicInit()
{
    P_SW2 = 0xc0;   // SCL(3.2) SDA(3.3)
    I2CCFG = 0xff;  // Turn on iic  Host mode   The highest speed 
    I2CMSST = 0x00; // Close the interrupt   Standby mode 
}

// The time delay function , The crystal oscillator of single chip microcomputer is 30M

void delay_ms(unsigned int ms)
{                        
        while(ms)
        {
          unsigned char i=39, j=243;
          do
          {while (--j);}
          while (--i);
                ms--;
          }
         return;
}

// Waiting for leisure

void Wait() 
{
    while (!(I2CMSST & 0x40));
    I2CMSST &= ~0x40;
}

// Start signal

void IIC_Start()
{
    I2CMSCR = 0x01;     // send out START command 
    Wait();
}

// End signal

void IIC_Stop()
{
    I2CMSCR = 0x06;     // send out STOP command 
    Wait();
}

// Wait and send ACK

void IIC_Wait_Ack()
{
    I2CMSCR = 0x00;                             // Set up ACK The signal 
    I2CMSCR = 0x05;                             // send out ACK command 
    Wait();
}

// Write Bytes

void Write_IIC_Byte(unsigned char dat)
{
    I2CTXD = dat;         // Write data to the data buffer 
    I2CMSCR = 0x02;       // send out SEND command 
    Wait();
}

// Write instructions

void Write_IIC_Command(unsigned char IIC_Command)
{
       IIC_Start();
       Write_IIC_Byte(0x78);            //Slave address,SA0=0
       IIC_Wait_Ack();       
       Write_IIC_Byte(0x00);           //write command
       IIC_Wait_Ack();       
       Write_IIC_Byte(IIC_Command);
       IIC_Wait_Ack();       
       IIC_Stop();
}

// Writing data

void Write_IIC_Data(unsigned char IIC_Data)
{
        IIC_Start();
        Write_IIC_Byte(0x78);                        //D/C#=0; R/W#=0
        IIC_Wait_Ack();       
        Write_IIC_Byte(0x40);                        //write data
        IIC_Wait_Ack();       
        Write_IIC_Byte(IIC_Data);
        IIC_Wait_Ack();       
        IIC_Stop();
}

// write in OLED Bytes of

void OLED_WR_Byte(unsigned dat,unsigned cmd)
{
      if(cmd)
      {
           Write_IIC_Data(dat);
      }
      else
      {
                                               
           Write_IIC_Command(dat);                                                         
      }
}

// Write the specified font

void fill_picture(unsigned char dat)
{
         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); 
                   for(n=0;n<128;n++)
                   {
                       OLED_WR_Byte(dat,1);
                   }
         }
}

// eliminate OLED The screen

void OLED_Clear(void) 
{ 
        u8 i,n;                    
        for(i=0;i<8;i++) 
        { 
                OLED_WR_Byte (0xb0+i,OLED_CMD);    // Set page address （0~7）
                OLED_WR_Byte (0x00,OLED_CMD);      // Set the display position — List the addresses 
                OLED_WR_Byte (0x10,OLED_CMD);      // Set the display position — Column address   
                for(n=0;n<128;n++)OLED_WR_Byte(0,OLED_DATA);
        } // Update display 

}

// initialization SSD1306                                           

void OLED_Init(void)
{      
         // Turn off display 
        OLED_WR_Byte(0xAE,OLED_CMD);//--display off

         // Set clock frequency division and RC Oscillator frequency 
         OLED_WR_Byte(0xD5,OLED_CMD);//set osc division
         OLED_WR_Byte(0x80,OLED_CMD);//

         // Set the multiplexing ratio 
         OLED_WR_Byte(0xA8,OLED_CMD);//--set multiplex ratio(1 to 64)
         OLED_WR_Byte(0x3F,OLED_CMD);//--1/32 duty    

         // Set the display offset , No offset setting 0
         OLED_WR_Byte(0xD3,OLED_CMD);//-set display offset
         OLED_WR_Byte(0x00,OLED_CMD);//
   
         // Set display start line 
         OLED_WR_Byte(0x40,OLED_CMD);//--set start line address 
      
         // Enable charge pump （0x10 Disable charge pump ）
         OLED_WR_Byte(0x8D,OLED_CMD);//set charge pump enable
         OLED_WR_Byte(0x14,OLED_CMD);//
        
         // Left and right display , Normal display 0x01（0xA0 Reverse left and right ）
         OLED_WR_Byte(0xA1,OLED_CMD);//set segment remap
        
         // Up and down display , Normal display 0xc8(0xc0 Up and down reversed )
         OLED_WR_Byte(0xC8,OLED_CMD);//Com scan direction
      
         // Set the hardware configuration of the column pins 
         OLED_WR_Byte(0xDA,OLED_CMD);//set com pin configuartion
         OLED_WR_Byte(0x12,OLED_CMD);//
        
         // Set contrast 【 The second maximum contrast 】
         OLED_WR_Byte(0x81,OLED_CMD); // contract control
         OLED_WR_Byte(0xFF,OLED_CMD);//--128

         // Set the duration of the precharge device 
         OLED_WR_Byte(0xD9,OLED_CMD);//Set Pre-Charge Period
         OLED_WR_Byte(0xF1,OLED_CMD);//
        
         // adjustment Vcomif The output of the regulator 
         OLED_WR_Byte(0xDB,OLED_CMD);//set Vcomh
         OLED_WR_Byte(0x30,OLED_CMD);//
               
         OLED_WR_Byte(0x00,OLED_CMD);//---set low column address
         OLED_WR_Byte(0x10,OLED_CMD);//---set high column address
       
         // Set page address 
         OLED_WR_Byte(0xB0,OLED_CMD);//--set page address       
         OLED_WR_Byte(0xD8,OLED_CMD);//set area color mode off
         OLED_WR_Byte(0x05,OLED_CMD);//
         OLED_WR_Byte(0xA4,OLED_CMD);//
        
         // Set to normal display ,1： Show ,0： No display 
         OLED_WR_Byte(0xA6,OLED_CMD);//--normal / reverse
       
         // open OLED
         OLED_WR_Byte(0xAF,OLED_CMD);//--turn on oled panel
         OLED_Clear();
} 

The main function ：

int main(void)
{
   iicInit();
   OLED_Init();
   while(1)
   {
        fill_picture(0xff);
        delay_ms(1000);
        fill_picture(0x00);
        delay_ms(200);
    }

}

  During the compilation process, we found that , LCD does not display , The end result is that the pin is not initialized .

    P5M0=0xff;
    P5M1=0x00;

The initialization test of the MCU pin is successful .