This is my Proteus project connected to 16f877a MCU with keypad

Dear All
Please see picture
This is my Proteus project connected to 16f877a MCU with keypad. when I press the key the result put to the portc
please advice, is this cct is correct?. meanwhile please send me a sample ASM code for this cct to understand the operation of keypad.
Thanks

PA3040 said:

Dear All
Please see picture
This is my Proteus project connected to 16f877a MCU with keypad. when I press the key the result put to the portc
please advice, is this cct is correct?. meanwhile please send me a sample ASM code for this cct to understand the operation of keypad.
Thanks

Click to expand...

Where is the picture?

---------- Post added at 21:42 ---------- Previous post was at 21:06 ----------

See https://www.edaboard.com/threads/191625/#post802105

Not tested by me

---------- Post added at 21:45 ---------- Previous post was at 21:42 ----------

The logic is :-
Make 4 pin as input and 4 pin as out put.


1. Make a input as high.
2.scan 4 o/p pins continuously if any of them as high read the particular key.

So make changes in the code given in the above link.

---------- Post added at 21:50 ---------- Previous post was at 21:45 ----------

///////////////////////////////////////
View the technical report:
http:/blog.iplussoft.com/pic_keypad_lcd.pdf

Download the assembly source file (.asm):
http:/blog.iplussoft.com/asm_pic_lcdkeypad.zip

Visit the official project site:
**broken link removed**

PA3040 said:

View attachment 70831Dear All
Please see picture
This is my Proteus project connected to 16f877a MCU with keypad. when I press the key the result put to the portc
please advice, is this cct is correct?. meanwhile please send me a sample ASM code for this cct to understand the operation of keypad.
Thanks

Click to expand...

As far as hardware connections go, there isn't much to say. Since, it all really depends on the code. The keypad connection is correct, but the code must use the connection as shown. You should use resistors for the LEDs, between the port pins and the LED anodes. For simulation, you should use "active" LEDs, not just "device" ones. Go to the window, where you select parts (p on keyboard). Type in LED. 2 places below the default selected part are the "active" LEDs for simulation.

Hope this helps.
Tahmid.