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...
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?
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.
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.
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..>??
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', :,:,<,=,>,?
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....
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...
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?
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?
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...