problem with key pad matrix interfacing - Electronic Circuits Projects Diagrams Free

sachin.kolkar · 5th May 2008, 04:02 AM

hi,
i m facing problem with 4X4 keypad matrix interfacing with PIC16F72 uc
When i run the program with simulator it works fine... one port is i am using for the key value using LED display .
when i connect the led & key board matrix , LED's are toggles continuesly in random manner
here is my code

Code:

#define keyport PORTB           //Keypad Port
#define keyportddr TRISB      //Data Direction Register
static char keytab[17]={0,1,2,3,10,4,5,6,11,7,8,9,12,13,0,14,15};
unsigned char keyval;   //A variable
void key_init();
unsigned char get_key();
 unsigned char i,key=1,j;
 void compare();
int main()
{
 DDRD=0x00;
 PORTD=0x00;
 DDRA=0xC0;
 PORTA=0xFF;
while(1)
{
 key_init();

get_key();


}
}

/*
+---------------------------------------+
| Prototype: void key_init(void);       |
| Return Type: void                     |
| Arguments: None                       |
| Description: Initialize ports and     |
|              Keypad.                  |
+---------------------------------------+
*/
void key_init(){
        keyportddr = 0xF0;
        keyport = 0xFF;
       

}

/*
+-----------------------------------------------+
| Prototype: unsigned char get_key(void);       |
| Return Type: unsigned char                    |
| Arguments: None                               |
| Description: To read key from the keypad      |
+-----------------------------------------------+
*/
unsigned char get_key(){
       key=1;
        for(i=0;i<4;i++){               //Loop for 4 rows
                keyport &=~(0x01<<i);   //Make rows low one by one
                        if(PORTB.F4==0){
                         //check COL1
                                while(!(keyportpin & (1<<col1)));
                                 
                                //wait for release
                                PORTD=keytab[key];
                                return key;
                                //return pressed key value
                        }
                        if((PORTB.F5==0))){
                         //Check COL2
                                key += 1;
                                //Second key pressed
                                while(!(keyportpin & (1<<col2)));
                                //wait for release
								PORTD=keytab[key];
                                return key;
                                //return key value
                        }
                        if(PORTB.F6==0){
                         //Check COL3
                                key += 2;
                                //Third key pressed
                                while(!(keyportpin & (1<<col3)));
                                //Wait for release
								               PORTD=keytab[key];
                                return key;
                                //Return value
                        }
                        if(PORTB.F7==0){
                         //check COL4
                                key += 3;
                                //Fourth key pressed
                                while(!(keyportpin & (1<<col4)));
                                //Wait for release
								PORTD=keytab[key];
                                return key;
                                //Return key value
                        }
                key +=4;        //Next row
                keyport |= 0x01<<i;
                //make read row high again
        }
        return 0;   //return false if no key pressed
}

PLZ help me guys......

Pommie · 5th May 2008, 04:29 AM

A quick look at your code suggests you have only posted part of it. There are no definitions for col1, col2, ddrd(???) etc. I also have no idea if you are including the right files and setting the config value. Could you also post which compiler you are using.

Mike.

sachin.kolkar · 5th May 2008, 07:28 AM

sorry, here is the code

Code:

#define keyport PORTB           //Keypad Port
#define keyportddr TRISB      //Data Direction Register
static char keytab[17]={0,1,2,3,10,4,5,6,11,7,8,9,12,13,0,14,15};
unsigned char keyval;   //A variable
void key_init();
unsigned char get_key();
 unsigned char i,key=1,j;
 void compare();
int main()
{
 TRISC=0x00;
 PORTC=0x00;
 while(1)
{
 key_init();

get_key();


}
}

/*
+---------------------------------------+
| Prototype: void key_init(void);       |
| Return Type: void                     |
| Arguments: None                       |
| Description: Initialize ports and     |
|              Keypad.                  |
+---------------------------------------+
*/
void key_init(){
        keyportddr = 0x0F;
        keyport = 0xFF;
       

}

/*
+-----------------------------------------------+
| Prototype: unsigned char get_key(void);       |
| Return Type: unsigned char                    |
| Arguments: None                               |
| Description: To read key from the keypad      |
+-----------------------------------------------+
*/
unsigned char get_key(){
       key=1;
        for(i=0;i<4;i++){               //Loop for 4 rows
                keyport &=~(0x01<<i);   //Make rows low one by one
                        if(PORTB.F4==0){
                         //check COL1
                                while(!(keyportpin & (1<<col1)));
                                 
                                //wait for release
                                PORTD=keytab[key];
                                return key;
                                //return pressed key value
                        }
                        if((PORTB.F5==0))){
                         //Check COL2
                                key += 1;
                                //Second key pressed
                                while(!(keyportpin & (1<<col2)));
                                //wait for release
								PORTD=keytab[key];
                                return key;
                                //return key value
                        }
                        if(PORTB.F6==0){
                         //Check COL3
                                key += 2;
                                //Third key pressed
                                while(!(keyportpin & (1<<col3)));
                                //Wait for release
								               PORTD=keytab[key];
                                return key;
                                //Return value
                        }
                        if(PORTB.F7==0){
                         //check COL4
                                key += 3;
                                //Fourth key pressed
                                while(!(keyportpin & (1<<col4)));
                                //Wait for release
								PORTD=keytab[key];
                                return key;
                                //Return key value
                        }
                key +=4;        //Next row
                keyport |= 0x01<<i;
                //make read row high again
        }
        return 0;   //return false if no key pressed
}

sachin.kolkar · 5th May 2008, 07:32 AM

i m using mikro C compiler......

mister_e · 5th May 2008, 07:22 PM

Hi,
why not using the built-in Keypad library?

If you have erratic results, to me, it sounds like you forgot to add some pull-up resistors.

HTH

arhi · 5th May 2008, 10:59 PM

Quote:

Originally Posted by sachin.kolkar

i m using mikro C compiler......

Why don't you check out the:
http://www.mikroe.com/pdf/keypad_board_schematic.pdf
http://www.mikroe.com/zip/keypad_board_examples.zip

you have there everything you need to make the keypad work

sachin.kolkar · 6th May 2008, 09:22 AM

Quote:

Originally Posted by mister_e

Hi,
why not using the built-in Keypad library?

i was use that built in keypad library...........but led's toggles without pressing any key.....

Quote:

If you have erratic results, to me, it sounds like you forgot to add some pull-up resistors.

HTH

i did it boss u can see this in my code,
if i m using key pad library i can't do this.....

Pommie · 6th May 2008, 09:36 AM

I can't see where in your code you are turning on the WPUs. I can't see where you write to a port to light LEDs.

Mike.

sachin.kolkar · 7th May 2008, 08:55 AM

Quote:

Originally Posted by Pommie

I can't see where in your code you are turning on the WPUs. I can't see where you write to a port to light LEDs.

Mike.

i m initialize PORTC for the LED light....

Pommie · 7th May 2008, 09:01 AM

Quote:

Originally Posted by sachin.kolkar

i m initialize PORTC for the LED light....

You set port C to output and set all pins low but then you write the keyboard value to Port D. The 16F72 doesn't even have a Port D.

Mike.

sachin.kolkar · 7th May 2008, 09:46 AM

Quote:

Originally Posted by sachin.kolkar

sorry, here is the code

Code:

#define keyport PORTB           //Keypad Port
#define keyportddr TRISB      //Data Direction Register
static char keytab[17]={0,1,2,3,10,4,5,6,11,7,8,9,12,13,0,14,15};
unsigned char keyval;   //A variable
void key_init();
unsigned char get_key();
 unsigned char i,key=1,j;
 void compare();
int main()
{
 TRISC=0x00;
 PORTC=0x00;
 while(1)
{
 key_init();

get_key();


}
}

/*
+---------------------------------------+
| Prototype: void key_init(void);       |
| Return Type: void                     |
| Arguments: None                       |
| Description: Initialize ports and     |
|              Keypad.                  |
+---------------------------------------+
*/
void key_init(){
        keyportddr = 0xF0;
        keyport = 0xFF;
       

}

/*
+-----------------------------------------------+
| Prototype: unsigned char get_key(void);       |
| Return Type: unsigned char                    |
| Arguments: None                               |
| Description: To read key from the keypad      |
+-----------------------------------------------+
*/
unsigned char get_key(){
       key=1;
        for(i=0;i<4;i++){               //Loop for 4 rows
                keyport &=~(0x01<<i);   //Make rows low one by one
                        if(PORTB.F4==0){
                         //check COL1
                                while(!(keyportpin & (1<<col1)));
                                 
                                //wait for release
                                PORTC=keytab[key];
                                return key;
                                //return pressed key value
                        }
                        if((PORTB.F5==0))){
                         //Check COL2
                                key += 1;
                                //Second key pressed
                                while(!(keyportpin & (1<<col2)));
                                //wait for release
								PORTC=keytab[key];
                                return key;
                                //return key value
                        }
                        if(PORTB.F6==0){
                         //Check COL3
                                key += 2;
                                //Third key pressed
                                while(!(keyportpin & (1<<col3)));
                                //Wait for release
								               PORTC=keytab[key];
                                return key;
                                //Return value
                        }
                        if(PORTB.F7==0){
                         //check COL4
                                key += 3;
                                //Fourth key pressed
                                while(!(keyportpin & (1<<col4)));
                                //Wait for release
								PORTC=keytab[key];
                                return key;
                                //Return key value
                        }
                key +=4;        //Next row
                keyport |= 0x01<<i;
                //make read row high again
        }
        return 0;   //return false if no key pressed
}

i corrected it ....
another problem is when i connect the RB4-RB7,
all portc leds start toggling..

Pommie · 7th May 2008, 09:54 AM

This suggests that you have not even managed to get this code to compile. As I said in my initial reply col1, col2 etc weren't defined, and they still aren't.

Are you posting all your code?

Mike.

sachin.kolkar · 7th May 2008, 10:00 AM

Quote:

Originally Posted by Pommie

This suggests that you have not even managed to get this code to compile. As I said in my initial reply col1, col2 etc weren't defined, and they still aren't.

Are you posting all your code?

Mike.

yes, i posted complete code , compiled & run the code, it works fine in simulator.....
while i m using the mikroC keypad library.....same problem encountering...

sachin.kolkar · 7th May 2008, 10:01 AM

i m using the same code for the atmel ATTINY2313

sachin.kolkar · 7th May 2008, 10:10 AM

when i initialise any port as input port & pull up resistors high..
but when i connect my DMM across that port pins it shows the low at that pins.....

Ex:
TRISB=0xFF;
PORTB=0xFF;

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5th May 2008, 04:29 AM	(permalink)
Pommie	A quick look at your code suggests you have only posted part of it. There are no definitions for col1, col2, ddrd(???) etc. I also have no idea if you are including the right files and setting the config value. Could you also post which compiler you are using. Mike.

5th May 2008, 07:32 AM	(permalink)
sachin.kolkar	i m using mikro C compiler...... __________________ hm:

5th May 2008, 07:22 PM	(permalink)
mister_e	Hi, why not using the built-in Keypad library? If you have erratic results, to me, it sounds like you forgot to add some pull-up resistors. HTH __________________ Steve ______________________ info@mister-e.org www.mister-e.org Last edited by mister_e; 5th May 2008 at 07:40 PM.

6th May 2008, 09:36 AM	(permalink)
Pommie	I can't see where in your code you are turning on the WPUs. I can't see where you write to a port to light LEDs. Mike.

7th May 2008, 09:54 AM	(permalink)
Pommie	This suggests that you have not even managed to get this code to compile. As I said in my initial reply col1, col2 etc weren't defined, and they still aren't. Are you posting all your code? Mike.

7th May 2008, 10:01 AM	(permalink)
sachin.kolkar	i m using the same code for the atmel ATTINY2313 __________________ hm:

7th May 2008, 10:10 AM	(permalink)
sachin.kolkar	when i initialise any port as input port & pull up resistors high.. but when i connect my DMM across that port pins it shows the low at that pins..... Ex: TRISB=0xFF; PORTB=0xFF; __________________ hm: