Line 50: Line 50:
  
  
=Usage guide==
+
==Usage guide==
 +
<syntaxhighlight>
 +
#include"keypad.h"
 +
#include"lcd.h"
 +
#include "delay.h" 
 +
 
 +
 
 +
/* Program to demonstrate the hex-Keypad interface*/
 +
int  main()
 +
{
 +
  uint8_t key;
 +
  LCD_Init(8,2,16);            /*Initialize the 2x16 LCD in 8-bit mode */
 +
  KEYPAD_Init();              /*Configure the ROWs and COLUMNs for keypad scanning*/
 +
 
 +
while(1)
 +
{
 +
key = KEYPAD_GetKey(); /*Get the Ascii value of the key Pressed */
 +
LCD_DisplayChar(key);  /*Display the key pressed */
 +
}
 +
 
 +
return 0;
 +
}
 +
 
 +
</syntaxhighlight>

Revision as of 17:44, 27 December 2014


KEYPAD

KEYPAD_Init

{{#Widget:LibTable}}
Defination void KEYPAD_Init()
Input Arguments none
Return Value none
Description This function configures the rows and columns for keypad scan.
  • ROW lines are configured as Output.
  • Column Lines are configured as Input.
Usage



KEYPAD_GetKey

{{#Widget:LibTable}}
Defination unsigned char KEYPAD_GetKey()
Input Arguments none
Return Value uint8_t--> ASCII value of the Key Pressed
Description This function waits till a key is pressed and returns its ASCII Value.

It follows the following sequences to decode the key pressed:

  • Wait till the previous key is released..
  • Wait for the new key press.
  • Scan all the rows one at a time for the pressed key.
  • Decodes the key pressed depending on ROW-COL combination and returns its

ASCII value.

Usage



Usage guide

#include"keypad.h"
#include"lcd.h"
#include "delay.h"   
 
 
/* Program to demonstrate the hex-Keypad interface*/
int  main()
{
  uint8_t key;
  LCD_Init(8,2,16);            /*Initialize the 2x16 LCD in 8-bit mode */
  KEYPAD_Init();               /*Configure the ROWs and COLUMNs for keypad scanning*/
 
	while(1)
	{
		key = KEYPAD_GetKey(); /*Get the Ascii value of the key Pressed */
		LCD_DisplayChar(key);  /*Display the key pressed */
	}
 
	return 0;
}