LCD12864 C language driver

#include

sbit RS=P2^0;

sbit RW=P2^1;

sbit EN=P2^2;

sbit CS1=P2^3;

sbit CS2=P2^4;

sbit RST=P2^5;

#define databus P0

#define uchar unsigned char

#define startline 0xc0

#define displayon 0x3f

#define startcolumn 0x40

#define page 0xb8

void init();

void clearscreen(uchar);

void readbusy();

void writecmd(uchar);

void writedata(vol);

//fly readdata();

void main()

{ 

flying i,j;

/*-- Text: Meng --*/

/*-- Songti 12; The corresponding dot matrix under this font is: width x height = 16x16 --*/

uchar code str[][16]={

0x00,0x10,0x10,0x10,0x11,0x11,0x91,0x11,0xF9,0x15,0x13,0x11,0x10,0x10,0x10,0x00,

0x40,0x40,0x40,0x7E,0x42,0x42,0x7E,0x43,0x42,0x7E,0x42,0x42,0x7E,0x40,0x40,0x00};

heat();

CS1=0;

CS2=1;

for(i=0;i<2;i++)

{

 writecmd(i|page);

 writecmd(startcolumn);

 for(j=0;j<16;j++)

 {

  writedata(str[i][j]);

 }

}

while(1);

}

void init()

{

RST=0;

RST=1;

CS1=0;

CS2=0;

writecmd(displayon);

writecmd(startline);

clearscreen(0);

}

void clearscreen(uchar select)

{

flying i,j;

switch(select)

{

 case 0:CS1=0;CS2=0;break;

 case 1:CS1=0;CS2=1;break;

 case 2:CS1=1;CS2=0;break;

 default:CS1=1;CS2=1;

}

for(i=0;i<8;i++)

{

 writecmd(i|page);

 writecmd(startcolumn);

 for(j=0;j<64;j++)

 {

  writedata(0);

 }

}

}

void readbusy()

{

RS=0;

RW=1;

do{

 databus=0xff;

 EN=1;

 ACC=databus;

 EN=0;

}while(ACC&0X80);

 }

void writecmd(uchar cmd)

{

readbusy();

RS=0;

RW=0;

databus=cmd;

EN=1;

EN=0;

}

void writedata(uchar dat)

{

readbusy();

RS=1;

RW=0;

databus=that;

EN=1;

EN=0;

}

/*

fly readdata()

{

flying tempo;

readbusy();

RS=1;

RW=1;

databus=0xff;

EN=1;

temp=databus;

EN=0;

readbusy();

RS=1;

RW=1;

databus=0xff;

EN=1;

temp=databus;

EN=0;

return temp;

}

*/

Pay special attention to the busy read subroutine. If this is not handled properly, the screen will be completely black.

I have wasted a lot of time on this. The Keil c51 compiler supports the use of the accumulator ACC in C code.

This is very good. Because I have written an assembly driver for 12864 before, and it can run normally on both simulation and actual hardware.

But after switching to C language and trying to write them one by one, I got stuck on the use of ACC.

READBUSY: CLR  RS

             SETB RW                          

BUSY_0: MOV DATABUS,#0FFH; When P0 port is used as a general input port to read data, 1 should be written first.

  SETB EN

  MOV  A,DATABUS

  CLR EN; When reading data continuously, you don’t need to write 1.

  JB   ACC.7,BUSY_0              

  RIGHT

Because MOV A, DATABUS is not easy to translate directly into C, and now the C code written after using ACC is disassembled and the assembly code is

Same, and the drive is working fine.