Keypad interfacing schematic

  • Thread starter smuscat
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  • #1
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Hi guys

Can please someone submit a circuit diagram for the resistors connections to the keypad of the below tutorial?
http://www.winpicprog.co.uk/pic_tutorial9.htm
"As the switches are all interconnected, we need a way to differentiate between the different ones - the four resistors on the interface board pull lines COL1 to COL4 high, these four lines are the ones which are read in the program. So in the absence of any switch been pressed these lines will all read high. The four ROW connections are connected to output pins, and if these are set high the switches will effectively do nothing - connecting a high level to a high level, results in a high level."
Thanks!
 

Answers and Replies

  • #2
berkeman
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Hi guys

Can please someone submit a circuit diagram for the resistors connections to the keypad of the below tutorial?
http://www.winpicprog.co.uk/pic_tutorial9.htm
"As the switches are all interconnected, we need a way to differentiate between the different ones - the four resistors on the interface board pull lines COL1 to COL4 high, these four lines are the ones which are read in the program. So in the absence of any switch been pressed these lines will all read high. The four ROW connections are connected to output pins, and if these are set high the switches will effectively do nothing - connecting a high level to a high level, results in a high level."
Thanks!
They are just for resistors that pull the COL (column) lines high, probably to 5V or 3.3V, whatever the PIC power supply is.
 
  • #3
256bits
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