How to interface Keypad matrix 4x4, 16F876A

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skquah
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How to interface Keypad matrix 4x4, 16F876A

Post by skquah »

Hello, all
I am a flow code 6 user.. I just want to learn how to interface the Keypad matrix 4x4 to my project using chip 16F876A..
I have tried with using Keypad matrix 3x4 with the flow code 6 and it work pretty good with the flow code simulation, as well
as I have tested with the hardware board which is my self built, It is functioning well and satisfactory..

The Keypad 3x4 flow code I used was from this forum article.. Thank you to the writer of this article..
I could not find the icon of this keypad 4x4 .. Although I have seen the other Generic Hex keypad 4x4, support by Matrix
but this Hex keypad is not available in the E Bay internet selling..

Now, I would like to attach my flow code program and schematic circuit of keypad 3x4, it was done successful with 3 push 'on' switch to activate 'on' the keypad loop.. In this program we can 'key-in' any number from 0 to 9 with * clear ' and ' # set ' ..
The program is able to enter 3 digit which is 000 to 999.. The flow code and schematic is with LCD display..

My problem is how to replace these 3 push 'on' switch with Column 4 of matrix 4x4 keypad.. I have tried to used ASCII conversion
for Key A= 65, B= 66, C= 67, D= 68 but it fail to work.. So I am seeking help from this forum, I will appreciate that..
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Thank you.. skquah

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Re: How to interface Keypad matrix 4x4, 16F876A

Post by skquah »

Benj or can anyone offer some help ?? Thank you..

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Re: How to interface Keypad matrix 4x4, 16F876A

Post by Benj »

Hello,

I've swapped the 4x3 keypad for a 4x4 keypad in the project. Is this what you need or is there something bigger? I can see that you've lost the * and # inputs which seem to do specific things. Would you replace these with hex keys e.g. 10-15 or A-F?
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skquah
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Re: How to interface Keypad matrix 4x4, 16F876A

Post by skquah »

Hi, Benj and others
1) The Hex keypad 4x4 that you mention is not the option I am looking at.. Because like what you mention I have to loose
out the * and # key, which 4x3 keypad * is for to 'clear' the digits and '#' key is for to exit from keypad after enter the digits..

2) Also, the hex keypad 4x4 is hard to find in the internet market.. Whereas, the keypad 4x4 that I posted is US$ 1.00 per
piece and can be bought easily from E-bay..

3) So far, I have tried many ways of writing the flow code with the posted keypad 4x4 and at last I have a find a solution
to interface the column 4 with the keys that I illustrate ..

4) Overall, I have done with the keypad interfacing but I still have other part to complete on the flow code, which my intended
project is for 000 ~ 999 timer to drive a valve..

5) Once I have done with this project, probably I will share this simple flow code that I write using this Keypad 4x4 for the
learning interest..

6) Thank you, Benj and I appreciate your response..

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