PIC keypad (i'm newbie)

[11max11]

hello all...
is that any information of keypad using the mplab write one...
i'm a newbie and no use this software before.
can anyone show me some easy code for the keypad.
because i don't know is that correct or not when i reseach from the website...

thx for helping

 

[ericgibbs]

hi,
Look at this site:



Or here:

https://www.tundraware.com/Software/PIC/keypad/

 

[11max11]

hi,
Look at this site:



Or here:

https://www.tundraware.com/Software/PIC/keypad/

if i using the IC 74C922 is that i can save a lot of time for write software??

 

[11max11]

how about using the IC74C922 ??
is that any problem when using the IC74C922 send data to the PIC16f877??

 

[kchriste]

You can use the IC74C922 if you want. You don't need to because the PIC can do it all by itself as mentioned on the pages posted by Eric.

 

[11max11]

You can use the IC74C922 if you want. You don't need to because the PIC can do it all by itself as mentioned on the pages posted by Eric.

ya i know.
but the thing i want is use the keypad combine with the PIC and get the output to control other thing.
is that i can use IC74C922 combine with the PIC then get the output from PIC?

 

[Nigel Goodwin]

Yes, you can do it either way - it all depends on which you prefer (and on what keypad you have).

 

[ericgibbs]

how about using the IC74C922 ??
is that any problem when using the IC74C922 send data to the PIC16f877??

hi,
A 74C922 can simplify your program.
Basically it scans a 4 * 4 keypad matrix, giving a output nibble 0 thru F [4bit]
also a another bit goes high to say a key has been pressed, use that for the Interrupt.

If you live in the UK, I'll send you one, FOC.

 

[blueroomelectronics]

It's available here but this is one of my favourite PIC Tip & Tricks (there are many more on the Microchip site in the app notes section. There's a section on a 4x4 keypad in there.

 

[gregmcc]

I like the resistor keypad idea. Here the 74c922 costs more than the pic itself

 

[blueroomelectronics]

I like the resistor keypad idea. Here the 74c922 costs more than the pic itself

Here too, and it's easy to do in software.

 

[11max11]

thx a lot for all helping me in here.....

 

[11max11]

i have a quetion for the IC74C922....
is that i press the button '0' the output will become "PA=0,PB=0,PC=0,PD=0"
then i press the output '1' will become "PA=0,PB=0,PC=0,PD=1" and so on..>??

or is other else?

 

[11max11]

is this correct??

#include <p16f877.inc>
PortB equ 06h
out_put MACRO var
movwf PortB
bsf PortB, var
bsc PortB, var

movf h'0A', w
out_put 4
movf h'0B', w
out_put 3
movf h'0C', w
out_put 2
movf h'0D', w
out_put 1

ENDM
END
thx for helping

 

[ericgibbs]

i have a quetion for the IC74C922....
is that i press the button '0' the output will become "PA=0,PB=0,PC=0,PD=0"
then i press the output '1' will become "PA=0,PB=0,PC=0,PD=1" and so on..>??
"PA=1,B=0,PC=0,PD=0]"
or is other else?

hi,
If you look at the TRUTH table as part of the 74C922 diagram I posted a few days ago, it will answer your question.

Summary:
the answer to this question is, for the #1 key, A=1,B=0,C=0,D=0,[you have reversed the pattern!],
also a pin goes high on the 74C922, [Data Available], while a key is pressed, use this to interrupt the PIC program.

If you 'OR' the 'A B C D' line input pattern with 30hex, it will give you ASCII '0', '1'... '9', :,:,<,=,>,?

 

[ericgibbs]

is this correct??

#include <p16f877.inc>
PortB equ 06h
out_put MACRO var
movwf PortB
bsf PortB, var
bsc PortB, var

movf h'0A', w
out_put 4
movf h'0B', w
out_put 3
movf h'0C', w
out_put 2
movf h'0D', w
out_put 1

ENDM
END
thx for helping

hi,
Whats the Macro supposed to do, its good practice to comment the Macro header with a description of the Macro's function.

Also as you have 'included the PIC type' you don't need to EQU the PORT's

 

[11max11]

hi,
If you look at the TRUTH table as part of the 74C922 diagram I posted a few days ago, it will answer your question.

Summary:
the answer to this question is, for the #1 key, A=1,B=0,C=0,D=0,[you have reversed the pattern!],
also a pin goes high on the 74C922, [Data Available], while a key is pressed, use this to interrupt the PIC program.

If you 'OR' the 'A B C D' line input pattern with 30hex, it will give you ASCII '0', '1'... '9', :,:,<,=,>,?

hihi..
thx i did't see clear for it...very thx...

 

[11max11]

hi,
Whats the Macro supposed to do, its good practice to comment the Macro header with a description of the Macro's function.

Also as you have 'included the PIC type' you don't need to EQU the PORT's

hihi....
i want to do is use the IC74C922 output send data to PIC16F877.
from PIC16F877 send the number i key in to infrared.
from other side PIC16F877 to accept it and display it to LCD...
i want to do encryption and decryption because this is a keylock...

 

[ericgibbs]

hihi....
i want to do is use the IC74C922 output send data to PIC16F877.
from PIC16F877 send the number i key in to infrared.
from other side PIC16F877 to accept it and display it to LCD...
i want to do encryption and decryption because this is a keylock...

hi,
Are you planning to detect a keypress, encode and IR transmit each key as it pressed?
Or
detect a keypress, encode, save in a key buffer and transmit the key buffer string when the user presses a 'ENTER or ACCEPT' key and will the keypad have a 'CANCEL or CLEAR' key?

Hope this is clear.

 

[11max11]

hi,
Are you planning to detect a keypress, encode and IR transmit each key as it pressed?
Or
detect a keypress, encode, save in a key buffer and transmit the key buffer string when the user presses a 'ENTER or ACCEPT' key and will the keypad have a 'CANCEL or CLEAR' key?

Hope this is clear.

hihi....
i want to do is the second one...but i need to add one more function for it. that is encryption and decryption it because the thing i want to do is key lock like i want to protect it...dun let it hack by someone...

thx for reply