AVR microcontroller - (three), ATMEGA16 drive 16 * 2 dot matrix character LCD module - 01

3. ATMEGA16 drives 16*2 dot matrix character LCD

3. (01) ATMEGA16 drives 16*2 dot matrix character LCD

This article is just a simple driver to make 1602 display, and does not use the part of reading data and reading status, nor does it use read and write detection (if you are interested, you can still write it here)

1. What kind of LCD should be used and how to drive it? Now I will post some pictures of the datasheet. It is so easy~~

1) Its pin description (I personally feel that if you want to know more, you can search it on the Internet~~ I just have a simple understanding here~)

There are only three pins that need attention here, RS, R/W, and E. These three pins are necessary for transmitting data. There is no need to introduce the others in detail~~ (The following program is written based on the timing diagram of these three pins!

2) (To be honest, I really don't want to go into detail, because many people think driving this 1602 is too simple~~ so I try to be concise) Basic operation timing

1 Read status: Input: RS=L, RW=H, E=H Output: D0~D7=status word

2 Write command: Input: RS=L, RW=L, D0~D7=command code, E=H Output: None

3 Read data: Input: RS=H, RW=H, E=OK Output: D0~D7=data

4 Write data: Input: RS=H, RW=L, D0~D7=data, E=high pulse Output: None

Note that since we don’t focus on reading, the important thing to look at above is the write timing and the timing parameters! ! ! !

(I don't need to explain too much here, but please note that 1602 is used to display data. Those functions such as read status and read data are not used for the time being, so I will not introduce them here for the time being. So, let's just use write instructions and write data directly. If you look closely, you will find that there is only one difference between write instructions and write data~~~~ that is, RS is low for write instructions; otherwise~~~)

3) Status word description

The read/write detection mentioned later is not needed for the time being, that's because we give it a delay, but if you want to use it, then take a good look at the datasheet~~~~ (To be honest: I don't know how to use the status word yet, if I do, I'll post back later~~haha)

4) RAM address map

5) Instruction description (this is the key point~~ you can find the above as long as you find the datasheet~~~ ah~~ so annoying )

5.1 Initialization settings:

5.1.1 Display mode settings:

Just write instruction 0x38

5.1.2 Display switch and cursor setting

This is very simple. I have also watched teacher Guo Tianxiang's teaching video~~He used this to explain~~Hehe

5.2 Data Control (I’m so tired, I really don’t want to write anymore, just post the pictures~~)

The read data and write data in the picture are the read timing and write timing. They are all above, so I won’t post them~~

Okay, I simulated the picture

Finally, the program~~

//------------------------------------------------------------------------------
//LCD1602 display program
#include "ioavr.h"
#include "intrinsics.h"
//------------------------------------------------------------------------------
typedef unsigned char uchar;
typedef unsigned int uint;
//------------------------------------------------------------------------------
//RS, RW, EN pin output high and low level macro definition
#define lcd_rs_1 PORTB|=1
#define lcd_rs_0 PORTB&=~1
#define lcd_rw_1 PORTB|=2
#define lcd_rw_0 PORTB&=~2
#define lcd_en_1 PORTB|=4
#define lcd_en_0 PORTB&=~4
//------------------------------------------------------------------------------
#define data_port PORTA
#define busy 0x80
#define xtal 8
//------------------------------------------------------------------------------
uchar __flash str0[]={"This is a LCD-!"};
uchar __flash str1[]={"Designed by ME"};
//------------------------------------------------------------------------------
//Delay 1ms function
void delay_1ms()
{
  uint i;
  for(i=1;i<(uint)(xtal*143-2);i++);
}
//------------------------------------------------------------------------------
//Delay nms function
void delay_nms(uint n)
{
  uint i=0;
  while(i  {
    delay_1ms();
    i++;
  }
}
//------------------------------------------------------------------------------
//LCD write data function
void lcd_write_data(uchar dat)
{
  lcd_rs_1;
  lcd_rw_0;
  data_port=dat;
  delay_1ms();
  lcd_en_1;
  delay_1ms();
  lcd_en_0;
}
//------------------------------------------------------------------------------
//LCD write command function
void lcd_write_command(uchar com)
{
  lcd_rs_0;
  lcd_rw_0;
  data_port=com;
  delay_1ms();
  lcd_en_1;
  delay_1ms();
  lcd_en_0;
}
//------------------------------------------------------------------------------
//LCD initialization function
void lcd_init()
{
  lcd_write_command(0x01);
  delay_1ms();
  lcd_write_command(0x38);
  delay_1ms();
  lcd_write_command(0x0c);
  delay_1ms();
  lcd_write_command(0x06);
  delay_1ms();
}
//------------------------------------------------------------------------------
//LCD display function
void lcd_display()
{
  uint num;
  lcd_write_command(0x80);
  for(num=0;num<16;num++)
  {
    lcd_write_data(str0[num]);
    delay_1ms();
  }
  lcd_write_command(0x80+0x40);
  for(num=0;num<16;num++)
  {
    lcd_write_data(str1[num]);
    delay_1ms();
  }
}
//------------------------------------------------------------------------------
//main
void main()
{
  delay_nms(100);
  DDRA=0XFF;
  PORTA=0X00;
  DDRB=0XFF;
  PORTB=0X00;
 
  lcd_init();
  lcd_display();
  while(1);
}