4x4 Keypad with PIC18F4520

[devilaurora]

keypad 4x4

Can anyone help me? I need to get a code for this 4x4 Keypad with the PIC18F4520, and i have been looking around the net for hours and hours, but i have not come across what i need. I could have miss some out as i simply don't udnerstand a thing...

I need to hand in this research in like 2 or 3 days time. Could anyone help? I have totally no idea how to go about now, considering how tired and sleepy i have been these days...

Thanks in advance.

 

[blueroomelectronics]

4x4 keypad

Guess it would have helped if you paid attention in class.

 

[devilaurora]

4x4 keypad how to make

The lecturers never exactly taught us how to do C programing, especially since this Keypad is something we have never touched before during class. The point now is that i need research materials, such as sample codes that i can possibly cite.

I will really appreciate it if someone could help me.

 

[pschandrareddy]

4 x 4 keypad

i can help you to have clear idea and i can guid to do code and hardware but i cant give you the source code............

then let me know.. will you?

 

[haripanangad]

p18f4520 keypad code

here is a method... but dont have the code .......
The advantage of this system is that it doesnt need any external power cktry and simple.... and also works perfectly

First of all a lookup table has to be created. here port b is used. Out 0x0F to PORT B, then out 0xF0 to Port B. Then OR the result and store it in a buffer. ie if no keys r pressed then the value in buffer will be 0XFF.
Now for example, if key 4 of the above figure is pressed, 0X0E will be the value when 0x0F is outputted from PortB. (here B0 will become 0 as the switch is pressed (00001110)). On the other hand, 0XE0 will be the value when 0XF0 is outputted (B4 becomes 0 (11100000)). when ORed the value in buffer will be 0xEE (x=0XEE). Now assign 0XEE with value 4.
Like this way make look up table for the whole keys. Using switch statement, a particular number could be assigned to the value in buffer.

Try this and reply back..............

 

[evileggtart]

how to use keypad p18f4520

Guess it would have helped if you paid attention in class.

lame

 

[blueroomelectronics]

4x4 keypads

Guess it would have helped if you paid attention in class.

lame

took you a month an a half to come up with that?

 

[sudat]

Re: p18f4520 keypad code

Hello,


I found ur method useful for my app. I have written code using ur method for scanning 3 x 3 matrix keypad. However, it is not generating all 9 codes for 9 keys.
Could u please find the bug in my code ?

// Make rows output and columns input
Configure_PortB_as_Output(); // Set Row as Output
Configure_PortC_as_Output(); // Set Column as Output
LATBbits.LATB2 = 0; // Write Row
LATBbits.LATB1 = 0; // Write Row
LATBbits.LATB0 = 0; // Write Row
LATCbits.LATC3 = 1; // Write Column
LATCbits.LATC2 = 1; // Write Column
LATCbits.LATC1 = 1; // Write Column
Configure_PortB_as_Input(); // Set Row as Input
u16Row = PORTB;
Configure_PortC_as_Input(); // Set Row as Input

// Make columns output and rows input
Configure_PortB_as_Output(); // Set Row as Output
Configure_PortC_as_Output(); // Set Column as Output
LATBbits.LATB2 = 1; // Write Row
LATBbits.LATB1 = 1; // Write Row
LATBbits.LATB0 = 1; // Write Row
LATCbits.LATC3 = 0; // Write Column
LATCbits.LATC2 = 0; // Write Column
LATCbits.LATC1 = 0; // Write Column
Configure_PortC_as_Input(); // Set Column as Input
u16Column = PORTC;
Configure_PortB_as_Input(); // Set Column as Input

u16ScanStatus = ((u16Row << 4) | u16Column);

Thank You,

Sunil Sawant

here is a method... but dont have the code .......
The advantage of this system is that it doesnt need any external power cktry and simple.... and also works perfectly

First of all a lookup table has to be created. here port b is used. Out 0x0F to PORT B, then out 0xF0 to Port B. Then OR the result and store it in a buffer. ie if no keys r pressed then the value in buffer will be 0XFF.
Now for example, if key 4 of the above figure is pressed, 0X0E will be the value when 0x0F is outputted from PortB. (here B0 will become 0 as the switch is pressed (00001110)). On the other hand, 0XE0 will be the value when 0XF0 is outputted (B4 becomes 0 (11100000)). when ORed the value in buffer will be 0xEE (x=0XEE). Now assign 0XEE with value 4.
Like this way make look up table for the whole keys. Using switch statement, a particular number could be assigned to the value in buffer.

Try this and reply back..............