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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
matrix keypad prog (by SEGAR)
hi, i wanna make programming with matrix keypad use password for operation any output ,but i don't have any idea for it, please if have any one done this programming in ldmicro please help to upload some information.

thanks
Sat Apr 18 2015, 03:20:39
(no subject) (by SEGAR)
HI, this is not help me really, because in C Language is easily people are can makid,i not use c language to write programming in the MCU. i only use ladder language but i do no how to makid circuits to interface with pic16f887 / AT89C51 MCU with keypad or LCD display. i can see people are using Data connection witout use UART . if any one done before please send circuits and some information on this .

YOU CAN THE CIRCUITS DIAGRAM IN THE ATTACHMENTS

THANK YOU
Tue Apr 28 2015, 01:59:21, download attachment LCD INTERFACE USING DATA CONNECTION.docx
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