Trouble in running 4*4 keypad with my esp32wroom

Projects General Guidance
1

Hi,
I want to esp32wroom with keypad(4*4) and ILI9341(2.8inch TFT LCD display).
When i connect them one at a time with my esp32 they both work fine.
Below is my pinout connection which worked.

For screen i used following pins of esp32 -> 5,16,17,18,23 (i have given power to display by esp32)

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byte pin_rows[ROW_NUM] = {19, 16, 15, 23}; // Row pin numbers
byte pin_column[COLUMN_NUM] = {2,4,5,18}; // Column pin numbers

Since both of them use some common pins when i used them separately, so i need to change my pinout diagram for using them together. So I kept the same connection for the screen and changed the connection for the keypad but it printed something gibberish.

Could u help me out to understand which pins i can use for the keypad without changing pins which my screen are using.

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2

this pinout connection doesnt work
byte pin_rows[ROW_NUM] = {36,39,32,33}; // Row pin numbers
byte pin_column[COLUMN_NUM] = {19,4,34,35}; // Column pin numbers

3

I moved your topic to a more appropriate forum category @av-jain.

The Nano ESP32 category you chose is only used for discussions directly related to the Arduino Nano ESP32 board.

In the future, please take the time to pick the forum category that best suits the subject of your question. There is an "About the _____ category" topic at the top of each category that explains its purpose.

Thanks in advance for your cooperation.

4

What pinout worked in the only keyboard running test?

1 Like
5

Does it work with just keypad.h alone and then fail with the addition of the ILI9341 ?

6

byte pin_rows[ROW_NUM] = {19, 16, 15, 23}; // Row pin numbers
byte pin_column[COLUMN_NUM] = {2,4,5,18}; // Column pin numbers
This worked out for me

7

Good.

8

I tried runnig it with just keypad.h only but it fails, I think there is no issue with the library, but the issue seems to be like I can't use some pins with my keypad of esp32.
Is there some pins which cannot be used with keypad of esp32

10

GPIO34 - 39 are input only.
And they have no internal pull-ups.
If Keypad.h uses "INTERNAL_PULLUP" then it would not work - until external pull-ups are placed.
Since the Columns are outputs, you will have to use other GPIO's for those.

11

Thanks for the telling me whats the problem but, can you also tell me which other 8 pins I can use for keypad other than (5,16,17,18 and 23).

12

I was recently referred to the list in the following article. It's good information, even though it doesn't include the full scoop on 34-39.

ESP32 Pinout Reference: Which GPIO pins should you use? | Random Nerd Tutorials

Use anything marked 'ok' without notation (GPIO13, 16-33) .

34-39 are useable, if not as outputs - or in the carefree, Arduino sense of "useable".

13

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