LCD
Revision as of 14:24, 28 December 2014 by Explorer (Talk | contribs)

LCD

LCD_Init

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Defination void LCD_Init ( uint8_t v_lcdMode_u8, uint8_t v_lcdNoOfLines_u8, uint8_t v_MaxCharsPerLine_u8)
Input Arguments *uint8_t: required Mode 4/8-bit
*uint8_t: Number of lines of LCD
*uint8_t: Number of Chars per line
Return Value none
Description This function is used to initialize the lcd.
It initializes the LCD for selected mode(4/8-bit) and Type(16x2/16x1 etc)
Usage LCD_Init(8,2,16) //Initialize 2x16 LCD in 8-bit Mode
LCD_Init(4,2,16) //Initialize 2x16 LCD in 4-bit Mode
LCD_Init(4,4,16) //Initialize 4x16 LCD in 8-bit Mode

LCD_Clear

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Defination void LCD_Clear()
Input Arguments none.
Return Value none.
Description This function clears the LCD and moves the cursor to beginning of first line
Usage



LCD_GoToLine

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Defination void LCD_GoToLine(uint8_t v_lineNumber_u8)
Input Arguments uint8_t: Line number to move the cursor.
Return Value none
Description This function moves the Cursor to beginning of the specified line. If the requested line number is out of range, it will not move the cursor.

Note: The line numbers run from 1 to Maxlines.
To avoid the confusion the below enums has to be used for selecting lines.
For four line LCD the enums are as below:

  • E_LcdLineOne
  • E_LcdLineTwo
  • E_LcdLineThree
  • E_LcdLineFour
Usage

LCD_GoToLine(1); //Moves the cursor to beginning of first line LCD_GoToLine(E_LcdLineOne); //Recommended usage

LCD_GoToNextline

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Defination void LCD_GoToNextLine()
Input Arguments none
Return Value none
Description This function moves the Cursor to beginning of the next line. If the cursor is on last line and NextLine command is issued then it will move the cursor to first line.
Usage

LCD_GoToNextline(); //Moves the cursor to beginning of next line.

LCD_SetCursor

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Defination void LCD_SetCursor(char v_lineNumber_u8,char v_charNumber_u8)
Input Arguments *row: line number(line1=1, line2=2)
For 2line LCD the I/P argument should be either 1 or 2.
  • col: char number.
    For 16-char LCD the I/P argument should be between 0-15.
Return Value none
Description This function moves the Cursor to specified position.
  • Note:If the Input(Line/Char number) are out of range then no action will be taken
Usage

LCD_SetCursor(1,10); //Moves the cursor to 1st line 11th char. LCD_SetCursor(5,10); //No action taken as line 5 is out of range

LCD_CmdWrite

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Defination void LCD_CmdWrite( uint8_t v_lcdCmd_u8)
Input Arguments 8-bit command supported by LCD.
Return Value none
Description This function sends a command to LCD.
Some of the commonly used commands are defined in lcd.h.
For more commands refer the data sheet.
The behaviour is undefined if unsupported commands are sent.
Usage

LCD_CmdWrite(0x0c); //Sets display On and Cursor Off LCD_CmdWrite(CMD_DISPLAY_ON_CURSOR_OFF); //Recommended

LCD_DisplayChar

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Defination void LCD_DisplayChar( char v_lcdData_u8)
Input Arguments uint8_t: ASCII value of the char to be displayed.
Return Value none
Description This function sends a character to be displayed on LCD.
Any valid ascii value can be passed to display the respective character
Usage

LCD_DisplayChar(65); //Displays 'A' on LCD
LCD_DisplayChar(0x41); //Displays 'A' on LCD
LCD_DisplayChar('A'); //Recommended usage

LCD_DisplayString

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Defination void LCD_DisplayString(char *p_stringPointer_u8)
Input Arguments char*:String(Address of the string) to be displayed.
Return Value none
Description This function is used to display the ASCII string on the lcd.
Usage 
 
void main()
{
   char myString[]={"hello, world"};
   LCD_DisplayString(myString);
   LCD_DisplayString("good morning");
}

LCD_ScrollMessage

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Defination void LCD_ScrollMessage(uint8_t v_lineNumber_u8, char *p_msgPointer_u8)
Input Arguments
  • uint8_t: Line number on which the message has to be scrolled
  • char *: pointer to the string to be scrolled
Return Value none
Description This function scrolls the given message on the specified line.
If the specified line number is out of range then the message will be scrolled on first line.
  • Note: Leave 7-8 spaces at the beginning and 1 space at the end of the message to be scrolled.
Usage

LCD_ScrollMessage(" Welcome to embedded programming ");

LCD_DisplayDecimalNumber

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Defination void LCD_DisplayNumber(uint32_t v_DecNumber_u32, uint8_t v_numOfDigitsToDisplay_u8 )
Input Arguments
  • uint32_t: Number to be displayed on the LCD.
  • uint8_t : Number of digits to be displayed
Return Value none
Description This function is used to display a max of 10digit decimal number.
2nd parameter specifies the number of digits from the right side to be displayed

The output for the input combinations is as below

  • (12345,4) then 4-digits ie. 2345 will be displayed
  • (12345,6) then 6-digits ie. 012345 will be displayed
  • (12345,C_DisplayDefaultDigits_U8) then 12345 will be displayed.
Usage

uint32_t decNumber = 123456;
LCD_DisplayDecimalNumber(decNumber,5); //Display last 5-digits of Number
LCD_DisplayDecimalNumber(12345,4); //Display last 4-digits of number

LCD_DisplayHexNumber

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Defination void LCD_DisplayHexNumber(uint32_t v_hexNumber_u32, uint8_t v_numOfDigitsToDisplay_u8)
Input Arguments
  • uint32_t: Hexadecimal Number to be displayed on the LCD.
  • uint8_t : Number of digits to be displayed
Return Value none
Description This function is used to display a max of 10digit hex number.
2nd parameter specifies the number of digits from the right side to be displayed .

The output for the input combinations is as below

  • (0x12AB,3) then 3-digits ie. 2AB will be displayed
  • (0x12AB,6) then 6-digits ie. 0012AB will be displayed
  • (0x12AB,C_DisplayDefaultDigits_U8) then 12AB will be displayed.
Usage

uint32_t hexNumber = 0x123456;
LCD_DisplayHexNumber(hexNumber,5); //Display last 5-digits of hexNumber
LCD_DisplayHexNumber(0xABCDEF,4); //Display last 4-digits of number

LCD_DisplayBinaryNumber

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Defination void LCD_DisplayBinaryNumber(uint32_t v_binNumber_u32, uint8_t v_numOfBitsToDisplay_u8)
Input Arguments
  • uint32_t: Hexadecimal Number to be displayed on the LCD.
  • uint8_t: Number of bits to be displayed
Return Value none
Description This function is used to display the binary equivalent of the given number.
2nd parameter specifies the number of LSB to be displayed .

The output for the input combinations is as below

  • (10,4) then 4-LSB will be displayed ie. 1010
  • (10,8) then 8-LSB will be displayed ie. 00001010
  • (10,2) then 2-LSB will be displayed ie. 10
Usage

uint32_t Number = 0xABCD;
LCD_DisplayDecimalNumber(Number,16); //Display last 16-bits of Number
LCD_DisplayDecimalNumber(0x1234,8); //Display last 8-bits of number

LCD_DisplayFloatNumber

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Defination void LCD_DisplayFloatNumber(float v_floatNum_f32)
Input Arguments float: Number to be displayed on the LCD.
Return Value none
Description This function is used to display a floating point number. It supports 6digits of precision.
  • Note: Float will be disabled by default as it takes huge controller resources.
    It can be enabled by changing value of Enable_LCD_DisplayFloatNumber to 1 in lcd.h
Usage

float Number = 1234.5678;
LCD_DisplayFloatNumber(Number);
LCD_DisplayFloatNumber(3.33333);

LCD_Printf

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Defination void LCD_Printf(const char *argList, ...)
Input Arguments variable length arguments similar to printf
Return Value none
Description This function is similar to printf function in C. It takes the arguments with specified format and prints accordingly .

The supported format specifiers are as below.

  • %c: character
  • %d: decimal(16bit)
  • %l: decimal(32-bit)
  • %b: binary(16-bit)
  • %s: string
  • %f: float
  • %x: hexadecimal
Usage 
void main()
{
uint16_t decNumber=1234;//16-bit
uint16_t longDecimal=12345678;//32-bit
float floatNumber=1234.5678;
uint16_t hexNumber=0xABCD;
char myString[]={"hello, world};
 
LCD_Printf("%d %l %f %x %b %s",decNumber,longDecimal,floatNumber,hexNumber,hexNumber,myString);
LCD_Printf("D:%d,L:%l,F=%f,H:%x,Str:%s",1234,12345678,123.456,0xAB,"hello");
}

Usage Guide

/* Program to demonstrate the LCD library usage*/
#include"lcd.h"
#include"delay.h"
 
int main()
{
 char a_displayMsg_u8[]={"Good Morning"};
 char v_lcdData_u8='A';
 uint16_t v_number_u16= 1234u;
 
 
  LCD_Init(8,2,16);
  LCD_ScrollMessage(0,"            Program to illustrate the lcd library usage ");
 
 
  LCD_Clear();
  LCD_DisplayString("Hello, world");    /* Display the specified Message */
  LCD_GoToNextLine();
  LCD_DisplayString(a_displayMsg_u8);   /* Display the message stored in a string */
 
  DELAY_sec(2);
  LCD_Clear();
  LCD_DisplayString("Display Char\n");
  LCD_DisplayChar('X');             /* Display the specified Ascii character */
  LCD_DisplayChar(v_lcdData_u8);    /* Display the char stored in a variable */
 
 
  DELAY_sec(2);
  LCD_Clear();
  LCD_DisplayString("D:");
  LCD_DisplayDecimalNumber(1234,5);   /* Display the specified digits of a number */
  LCD_DisplayString(" H:");
  LCD_DisplayHexNumber(0xABCD,5);     /* Note here the num=1234, and digitsToDisplay=5 */
  LCD_GoToNextLine();                 /* The number displayed on LCD will be as below*/
  LCD_DisplayBinaryNumber(0xABCD,16); /* dec=01234, hex=0ABCD,
                                         bin=1010101111001101*/
 
 
 
  DELAY_sec(2);
  LCD_Clear();
  LCD_Printf("D=%d H=%x \n%b",v_number_u16,v_number_u16,v_number_u16);
 
 
 
  DELAY_sec(2);
  LCD_Clear();
  LCD_Printf("Enjoy Embedded \nProgramming");
  while(1);
 
  return 0;
  }
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