what is keypad, keypad interfacing with ATmega16,programming of lcd and keypad interfacing with ATmega16, simulation on protious, application. In this tutorial we are going to interface a 4×4 (16 key) keypad with ATMEGA32A AVR Microcontroller. We all know keypad is one of the most. The concept of interfacing a keypad with the ATmega16 is similar to interfacing it with any other microcontroller. The article of Interfacing keypad with can.

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Many application requires large number of keys connected to a computing system. We want to avoid all these troubles so we use some clever technique. The technique is called multiplexed matrix keypad. The rows R0 to R3 are connected to Input lines of Microcontroller. We can read the Value of R0 to R3 to get their pressed status. If they are high the button is NOT pressed.

As we have enabled internal pullups on them, these pullups keep atmefa16 value high when they are floating that means NOT connected to anything. And read R0 to R3 again.

This gives us status of the second column of keys.

Similarly we scan all columns. For example port A has. Lets say we selected column number C0, so we make it LOW i. GND or logic 0in the same atega16 we make all other columns high impedance i. So the only other possible state is all other columns are HIGH. This is shown in figure below. Red colour on column indicate high state while green is for low state. The above code make use of the LCD Library.

You can get more information on LCD Library here: The test circuit will be built around ATmega32 microcontroller. So we set up a basic ATmega32 circuit. The circuit will have the following: Compile the above program using AVR Studio compiler is avr-gcc.

The fuse bits must be set as following to enable external crystal as clock source. This complete our test. What I recommend the users is to get your basics strong. You need full understanding of C language concept and the full details of the device you are programming, this will save you lots of time. So please go and read the good book on C and the datasheet of AVRs before you dive in! We try to publish beginner friendly tutorials for latest subjects in embedded system as fast as we can.


If you like these tutorials and they have helped you solve problems, please help us in return. You can donate any amount as you like securely using a Credit or Debit Card or Paypal. Get quote online easily: Facing problem with your embedded, electronics or robotics project? We are here to help! Post a help request. Avinash Gupta is solely focused on free and high quality tutorial to make learning embedded system fun!

More Posts – Website. Hi Avinash, great tutorial again, but you diddnt add the. It would have helped to find out how your program actually works!! All the files are provided at the end! I think you should be more careful before complaining. This confuses the other readers. Hi Avinash, the objective was to remove my confusion!! Could this be adapted for my atmega48 mcu? Each undeclared identifier is reported only once. I got it working on the atmega When I hold down the 2 button the LCD flashes between 0 and 1 very fast.

When I hold down 3 button the same thing happens but flashes between 0 and 2. All the other buttons work properly.

How to interface keypad with AVR microcontroller (ATmega16)

I changed some things around and got it working. I put the lcd data on port C and the keypad on port B. All of the keys output as expected. Here is a youtube atmeba16.

Brendin Congratulation on your success in porting ahmega16 code to ATmega48! I mean, whenever I press the 2nd, ksypad and 4th keys, the display flashes between 0 and 1, 0 and 2, 0 and 3 respectively. Unlike his case, the problem did not solve by changing the ports…. U have to climb b4 u reach the hilltop, so b4 commentin plz check the complete archive of this website…. I understand ur point of view ….

If u have time can u atleast tell how can i connect an AtmegaXX to the RF toy car circuit … Correct me if i am wrong anywhere …. Another question is how can i increase aerial intetfacing transfer range if i bought a Interfacng module, for, currently i noe its limited to a modest span of some feet. Is it achieved with the aid of repeaters Power Boosting. How can we program AVR in such cases? Does it generate some kind of interrpt??? Somedays ago in a wireless robo-boat championship I saw that none of the boats were working.

Is it because all of them were trying to work at the same frequency? If problem persists increase the delay to 2ms.

4×3 Matrix Keypad Interface – AVR Tutorial

Thank you so much for this comment. Please give me matrix keypad interface code for PIC 16f84 microconttrolar in C language. Emran this is advance of C code.


You can change for different micro controller with vary few changes. No one can write code for every micro controller and compiler. If you know about atmega1 16f84 then change it according to your requirement. What changes should i make if i want to read multiple keys at same time. Thank you very much for such an elaborate tutorial.

Interfacing 4×4 keypad with AVR Atmega16 Microcontroller | ABlab Solutions

I was trying to interface atmfga16 4 x 4 key pad with MSPx, after few hick-ups in at,ega16 beginning I was able to debug the problems and resolve them. Once again thank you very much for your article.

Dear Avinash How to convert this program like mobile key pad say 1 key have 3 charters to display. Hi hi Avinash, Great tutorial. Thank you for this great tutorial. I need your help. I did not change anything only the microcontroller. I kept the c code as it is. I built it exactly as yours but i am not getting the digit in the LCD as yours. I am getting random keys.

4×4 Keypad Interfacing with AVR Microcontroller (ATmega32)

My question is the keypad has got 7 pins and could you please help me to find out which one is pin1 to pin7 and which pin is columns and rows. Another question is from other website I knterfacing found out that they connect the column with Ohms resistor and the row with 10K to ground, why?

Please tell me how can u detect the column i. This project was very helpful for me. Will this 4 x 3 matrix keypad work in Raspberry Pi 3? I am new in it and trying to interface matrix keypad with Ri using C.

Will your code work? However, each button must have: The implementation of a short and long button action. Kypad this I read the functions of Peter Dannegger that not seem the way to the case of a keypad.

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Avinash Avinash Intergacing is solely focused on free and high quality tutorial to make learning embedded system fun! More Posts – Website Follow Me: By Mayukh Banerjee – October 16, By Avinash – October 16,