NHD-0216KZW/ 0216SZW/ 0220DZW/ 0420DZW - (SPI)

Example code for NHD-0216KZW/ 0220DZW/ 0420DZW - (SPI)

#include <reg52.h>

sbit SCL = P3^4;
sbit SDOUT = P1^0;
sbit SDIN = P1^1;
sbit C_S = P3^3;

void delay(unsigned int n)				//Delay subroutine
{
	unsigned int i,j;
	for (i=0;i<n;i++)
  		for (j=0;j<250;j++)
  			{;}
}
 

void WriteCommand(unsigned char ins)
{
	unsigned char i;
	C_S=0;
	SCL = 0;
	SDOUT = 0; 	//RS = 0 (Command)
	SCL = 1;	//RS registered
	SCL = 0;	
	SDOUT = 0; 	//RW = 0
	SCL = 1;	//RW registered
	SCL = 0;
	
	for (i=0x80;i;i>>=1)
	{
		if((ins&0x80)==0x80)
		SDOUT = 1;
		else
		SDOUT = 0;
		ins=(ins<<1);
		SCL = 0;
		SCL = 1;
		SCL = 0;
	}
	
    C_S=1;	 
}

void WriteDataInit()
{
	
	C_S=0;
	SCL = 0;
	SDOUT = 1;	//RS = 1 (Data)
	SCL = 0;	//RS registered
	SCL = 1;
	SCL = 0;
	SDOUT = 0; 	//RW = 0
	SCL = 1;	//RS registered
	SCL = 0;

}
void WriteData(unsigned char dat)
{
	unsigned char i;
	for (i=0x80;i;i>>=1)
	{
		if((dat&0x80)==0x80)
		SDOUT = 1;
		else
		SDOUT = 0;
		dat=(dat<<1);
		SCL = 0;
		SCL = 1;
		SCL = 0;
	}
	
}

void init()
{
	WriteCommand(0x38);//function set
	delay(30);
	WriteCommand(0x06);//entry mode set
	delay(30);
	WriteCommand(0x02);//return home
	delay(30);
	WriteCommand(0x01);//clear display
	delay(30);
	WriteCommand(0x0c);//display on
	delay(30);
	WriteCommand(0x80);//line 1 character 1
	delay(30);
}

void main()
{
	char i=0x21, j;

	
	
	init();

	while(1)
	{	
		C_S = 1;
		WriteCommand(0x80);		//Line 1	

		WriteDataInit();
		//WriteDataInit() must only be executed once before starting to write data
		//if WriteDataInit() is executed between writes, the display will recognize the two bits as data bits and not RS/RW bits.  
		for(j=0; j<20; j++)
		{
			WriteData(i++);
			delay(10);
		}

		C_S = 1;			
		//Pulling C_S High means write data is completed
		//if next instruction to the display is data, must use WriteDataInit() first
		//if write command is executed without pulling C_S high, it will recognize the following instruction on the bus as data regardless
		WriteCommand(0xC0);		//Line 2
		
		WriteDataInit();
		for(j=0; j<20; j++)
		{
			WriteData(i++);
			delay(10);
		}
		
		C_S = 1;
		WriteCommand(0x94);		//Line 3

		WriteDataInit();
		for(j=0; j<20; j++)
		{
			WriteData(i++);
			delay(10);
		}


		C_S = 1;
		WriteCommand(0xD4);		//Line 4

		WriteDataInit();
		for(j=0; j<20; j++)
		{
			WriteData(i++);
			delay(10);
		}
		
	}
}