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LDmicro Forum - program keypad 4x3 for pic16f877a using ldmicro

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program keypad 4x3 for pic16f877a using ldmicro (by Mazlan)
Hi,
I facing a problem on creating program fpr pic 16f877a, how keypad 4x3 can be program. The project is digital lock.
Thanks.
Sat Feb 26 2011, 09:38:14
(no subject) (by Max)
Hi,
Do you mean (how to scan a 4x3 matrix keypad)

If answer is yes, then the easiest way will be to supply 3 different voltage to the column wire... and read on 4 analog input the voltage of the 4 line wire

Ex,
column #1 = 1 volt
column #2 = 2.5 volts
column #3 = 5 volts

So if you read between (450 and 560) 2.5V on analog line #1, you know that the key #2 has been pressed

and if you read more than (900) 5V on analog line #1, this is key #3

Hope this help
Sat Feb 26 2011, 21:41:22
(no subject) (by Mazlan)
Thanks Max, I'll try this option.
Mon Feb 28 2011, 03:06:31
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