Lập trình hiển thị LCD 4bit trên vi điều khiển 8051 với Mikroc

[myfriends214]

Đây là một bài học về lập trình hiển thị trên LCD 4-bit, trong project này sử dụng vi điều khiển 8051, ngôn ngữ lập trình là C, trình biên dịch Mikroc Pro for 8051.

Các hàm sử dụng trong project:

• Lcd_Init
• Lcd_Out
• Lcd_Out_Cp
• Lcd_Chr
• Lcd_Chr_Cp
• Lcd_Cmd

Định nghĩa hàm và ví dụ:

Prototype	void Lcd_Out(char row, char column, char *text);
Returns	Nothing.
Description	Prints text on Lcd starting from specified position. Both string variables and literals can be passed as a text. Parameters : row: starting position row number column: starting position column number text: text to be written
Requires	The Lcd module needs to be initialized. See Lcd_Init routine.
Example	// Write text "Hello!" on Lcd starting from row 1, column 3: Lcd_Out(1, 3, "Hello!");

Lcd_Out_CP

Prototype	void Lcd_Out_Cp(char *text);
Returns	Nothing.
Description	Prints text on Lcd at current cursor position. Both string variables and literals can be passed as a text. Parameters : text: text to be written
Requires	The Lcd module needs to be initialized. See Lcd_Init routine.
Example	// Write text "Here!" at current cursor position: Lcd_Out_CP("Here!");

Lcd_Chr

Prototype	void Lcd_Chr(char row, char column, char out_char);
Returns	Nothing.
Description	Prints character on Lcd at specified position. Both variables and literals can be passed as a character. Parameters : row: writing position row number column: writing position column number out_char: character to be written
Requires	The Lcd module needs to be initialized. See Lcd_Init routine.
Example	// Write character "i" at row 2, column 3: Lcd_Chr(2, 3, 'i');

Lcd_Chr_CP

Prototype	void Lcd_Chr_Cp(char out_char);
Returns	Nothing.
Description	Prints character on Lcd at current cursor position. Both variables and literals can be passed as a character. Parameters : out_char: character to be written
Requires	The Lcd module needs to be initialized. See Lcd_Init routine.
Example	// Write character "e" at current cursor position: Lcd_Chr_CP('e');

Lcd_Cmd

Prototype	void Lcd_Cmd(char out_char);
Returns	Nothing.
Description	Sends command to Lcd. Parameters : out_char: command to be sent Note: Predefined constants can be passed to the function, see Available Lcd Commands.
Requires	The Lcd module needs to be initialized. See Lcd_Init table.
Example	// Clear Lcd display: Lcd_Cmd(_LCD_CLEAR);

Available Lcd Commands

_LCD_FIRST_ROW	Move cursor to the 1st row
_LCD_SECOND_ROW	Move cursor to the 2nd row
_LCD_THIRD_ROW	Move cursor to the 3rd row
_LCD_FOURTH_ROW	Move cursor to the 4th row
_LCD_CLEAR	Clear display
_LCD_RETURN_HOME	Return cursor to home position, returns a shifted display to its original position. Display data RAM is unaffected.
_LCD_CURSOR_OFF	Turn off cursor
_LCD_UNDERLINE_ON	Underline cursor on
_LCD_BLINK_CURSOR_ON	Blink cursor on
_LCD_MOVE_CURSOR_LEFT	Move cursor left without changing display data RAM
_LCD_MOVE_CURSOR_RIGHT	Move cursor right without changing display data RAM
_LCD_TURN_ON	Turn Lcd display on
_LCD_TURN_OFF	Turn Lcd display off
_LCD_SHIFT_LEFT	Shift display left without changing display data RAM
_LCD_SHIFT_RIGHT	Shift display right without changing display data RAM

Sơ đồ nguyên lý:

8051 LCD

Code:
/*Share by dientudieukhien.net
MikroC Pro for Pic*/
// Lcd module connections
sbit LCD_RS at P2_0_bit;
sbit LCD_EN at P2_1_bit;

sbit LCD_D4 at P2_2_bit;
sbit LCD_D5 at P2_3_bit;
sbit LCD_D6 at P2_4_bit;
sbit LCD_D7 at P2_5_bit;
// End Lcd module connections

char txt1[] = "Embedded";
char txt2[] = "Projects";
char txt3[] = "Lcd 4 bit";
char txt4[] = "Tutorial";

char i; // Loop variable

void Move_Delay() { // Function used for text moving
Delay_ms(500); // You can change the moving speed here
}

void main(){

Lcd_Init(); // Initialize Lcd

Lcd_Cmd(_LCD_CLEAR); // Clear display
Lcd_Cmd(_LCD_CURSOR_OFF); // Cursor off
Lcd_Out(1,6,txt3); // Write text in first row

Lcd_Out(2,6,txt4); // Write text in second row
Delay_ms(2000);
Lcd_Cmd(_LCD_CLEAR); // Clear display

Lcd_Out(1,1,txt1); // Write text in first row
Lcd_Out(2,5,txt2); // Write text in second row

Delay_ms(2000);

// Moving text
for(i=0; i<4; i++) { // Move text to the right 4 times
Lcd_Cmd(_LCD_SHIFT_RIGHT);
Move_Delay();
}

while(1) { // Endless loop
for(i=0; i<8; i++) { // Move text to the left 7 times
Lcd_Cmd(_LCD_SHIFT_LEFT);
Move_Delay();
}

for(i=0; i<8; i++) { // Move text to the right 7 times
Lcd_Cmd(_LCD_SHIFT_RIGHT);
Move_Delay();
}
}
}

Nguồn: DIEN TU DIEU KHIEN .NET