Keypad Revision as of 17:44, 27 December 2014 by Explorer (Talk | contribs) (diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

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;
}