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Regarding : Matrix 4x4 keypad interfacing with dsPIC30F4011 controller

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Hello to all,
I am Working on dsPIC30F4011 microcontroller in MPLab in C programming. I need to use 4x4 matrix keypad. Please can any one suggest how can i interface that keypad with dsPIC30F4011 uController? and also kindly give programming instructions that need to be written in C code, like internal pull-up and all that. kindly provide solution as soon as possible...


Regards...
 

You're probably aware of this typical input array (4x4).
Sorry I don't know about programming the mcu.

3574765600_1489116905.png
 

hi,

I did not use that pic controller.

But i will give example coding for keypad.
below code is 8051 code for 4x4 matrix.
Code: 
#include<reg51.h>
#define lcd P0
#define key P2
void delay();
void datas(unsigned char);
void cmd(unsigned char);
void lcdint(unsigned char);
sbit rs=P0^4;
sbit en=P0^5;

unsigned char keypad[4][4]	= {'0','1','2','3',
															'4','5','6','7',
															'8','9','A','B',
															'C','D','E','F'};
unsigned char rowloc,colloc,keypress;
void main()
{
	lcd=0xF0;		//INTIALIZING LCD PORT
	key=0xF0;		//INTIALIZING KEYPAD PORT
	
	while(1)
	{
		do							//KEY RELECE CHECK
			{
				key=0xF0;
				ACC=key;
				ACC=ACC&0XF0;
			}while(ACC != 0XF0);
		do
		{
			do						//KEY PRESS CHECK
			{
				delay();
				ACC=key;
				ACC=ACC&0XF0;
			}while(ACC == 0XF0);
			
			delay();			//DEBOUNCE CHECK
			ACC=key;
			ACC=ACC&0XF0;
			}while(ACC == 0XF0);
	while(1)
	{
		key=0xFE;				//CHECK COL LOCATION
		ACC=key;
		colloc=ACC & 0xF0;
		if(colloc != 0xF0)
		{
			rowloc=3;
			break;
		}
		key=0xFD;
		ACC=key;
		colloc=ACC & 0xF0;
		if(colloc != 0xF0)
		{
			rowloc=2;
			break;
		}
		key=0xFB;
		ACC=key;
		colloc=ACC & 0xF0;
		if(colloc != 0xF0)
		{
			rowloc=1;
			break;
		}
		key=0xF7;
		ACC=key;
		colloc=ACC&0xF0;
		rowloc=0;
		break;	
	}
	if(colloc==0XE0)		//CHECK ROW LOCATION
		colloc=3;
	else if(colloc==0XD0)
		colloc=2;
	else if(colloc==0XB0)
		colloc=1;
	else
		colloc=0;
	lcdint(keypad[rowloc][colloc]);
}
}
void lcdint(unsigned char keypress)		//SEND TO LCD
	{
		cmd(0X28);
		delay();
		cmd(0X0E);
		delay();
		cmd(0X01);
		delay();
		cmd(0X06);
		delay();
		cmd(0X80);
		delay();
		datas('K');
		delay();
		datas('E');
		delay();
		datas('Y');
		delay();
		cmd(0XC2);
		delay();
		datas(keypress);
		delay();
		
	}
void cmd(unsigned char value)		//LCD COMMAND PROGRAM
{
	ACC=value;
	ACC=ACC>>4;
	ACC=ACC&0X0F;
	P0=ACC;
	en=1;
	P0=ACC;
	ACC=value;
	ACC=ACC&0X0F;
	P0=ACC;
	en=1;
	P0=ACC;
}

void datas(unsigned char value)		//LCD DATA PROGRAM
{
	ACC=value;
	ACC=ACC>>4;
	ACC=ACC&0X0F;
	P0=ACC;
	rs=1;
	en=1;
	P0=ACC;
	ACC=value;
	ACC=ACC&0X0F;
	P0=ACC;
	rs=1;
	en=1;
	P0=ACC;
	delay();
}
 

Hi,

There are 4 rows an 4 columns
Making 8 lines
Connect these 8 lines to a microcontroller port

Initialize all 8 ports for input with pullup

To the four keys of a row:
Set the (single) row to output LOW(leave all other signals input with pullup)
Wait some microseconds (for the signals to stabilize)
Read the port
Now a LOW at a column represents a pressed key in that row. Decode it as you like.
Then make all signals input pullup again.
Finished

Do this for all four rows periodically. I recommend to use a timer interrupt to read the complete keypad every 50ms.

Multiple key press (at once) is a problem. Max two pressed keys can be decoded safely. But if more keys are pressed you get wrong readings.
I recommend to focus on single pressed keys. Make a single one byte variable as key_variable.
Where "0" = no key pressed
And "1" to "16" = according the pressed key.
I also recommend to focus on single key press, so multiple key press are shown as "0" = no key pressed.

Klaus
 

Hello,
I have connected keypad in B port of dsPIC30F4011 from pin no. 2 To 9. but i don't know how to write instructions for all pull-up. please kindly suggest C code statements for the pull up. some statements i wrote for keypad and pull-up are as below....



ADCON1 = 0x0F; // for analogue to digital conversion
TRISB = 0xF0; // for B port as input for keypad

CNPU1bits.CN2PUE = 1; // enable pullup
CNPU1bits.CN3PUE = 1; // enable pullup




Regards...
 

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