Strange behavior LILYGO T-Display ESP32

Here we can discuss about the problem found
Post Reply
waldli
Posts: 23
Joined: Sat Sep 02, 2023 7:46 am
Has thanked: 2 times
Been thanked: 1 time

Strange behavior LILYGO T-Display ESP32

Post by waldli »

Hello everyone
I'm currently trying out the LILYGO T-Display ESP32
I wrote a short test program and checked the two integrated buttons on GPIO 0 and GPIO 35.
The GPIO 0 button is supposed to increment a variable and GPIO 35 is supposed to decrement it.
GPIO 0 does what it's supposed to but GPIO 35 counts down several times between 4 and 10.
What am I doing wrong? Or is there a software error?

Here is the program
-------------------------------------------------------------
pin.mode 0, input,pullup
pin.mode 35, input,pullup
a=12345
interrupt 0, go0,1
interrupt 35, go35,1
TFT.FILL 0
TFT.BRIGHTNESS 255
'TFT.IMAGE"/123.bmp"
pause 2000
TFT.RECT 0,0,240,135, TFT.RGB(50, 50, 250),1
TFT.RECT 10, 40,220,70, TFT.RGB(150, 150, 250),1,5
tft.text.color TFT.RGB(250, 2, 2)
TFT.TEXT.DRAW str$(a),120,50,7
tft.text.color 0
TFT.TEXT.DRAW "Starten",120,5,4
wait

go0:
wlog "pin 0"
a=a+1
TFT.RECT 10, 40,220,70, TFT.RGB(150, 150, 250),1,5
tft.text.color TFT.RGB(2, 2, 2)
TFT.TEXT.DRAW str$(a),120,50,7
pause 100
return

go35:
wlog "pin35"
a=a-1
TFT.RECT 10, 40,220,70, TFT.RGB(150, 150, 250),1,5
tft.text.color TFT.RGB(2, 2, 2)
TFT.TEXT.DRAW str$(a),120,50,7
pause 100
return
---------------------------------------------------------------

Kind regards
Waldemar
waldli
Posts: 23
Joined: Sat Sep 02, 2023 7:46 am
Has thanked: 2 times
Been thanked: 1 time

Re: Strange behavior LILYGO T-Display ESP32

Post by waldli »

lily.jpg
Here is the module
You do not have the required permissions to view the files attached to this post.
User avatar
cicciocb
Site Admin
Posts: 2781
Joined: Mon Feb 03, 2020 1:15 pm
Location: Toulouse
Has thanked: 592 times
Been thanked: 1990 times
Contact:

Re: Strange behavior LILYGO T-Display ESP32

Post by cicciocb »

You have probably bounces on the pin. Try to put a capacitor on the pin
User avatar
PeterN
Posts: 641
Joined: Mon Feb 08, 2021 7:56 pm
Location: Krefeld, Germany
Has thanked: 296 times
Been thanked: 357 times
Contact:

Re: Strange behavior LILYGO T-Display ESP32

Post by PeterN »

I think this GPIO doesn‘t have a pullup resistor to be activated.
I would try an external 10K to pullup the pin to 3V3

https://www.perplexity.ai/search/which- ... 65sluawWow
waldli
Posts: 23
Joined: Sat Sep 02, 2023 7:46 am
Has thanked: 2 times
Been thanked: 1 time

Re: Strange behavior LILYGO T-Display ESP32

Post by waldli »

Hello,

I debounced the button with a 22nF capacitor.
The behavior remained the same. After each key press,
the count went down by exactly 10 too many.

Regards
Waldemar
waldli
Posts: 23
Joined: Sat Sep 02, 2023 7:46 am
Has thanked: 2 times
Been thanked: 1 time

Re: Strange behavior LILYGO T-Display ESP32

Post by waldli »

Hello,
I just read your last posting
I'm trying with a pull-up resistor.

Regards
Waldemar
waldli
Posts: 23
Joined: Sat Sep 02, 2023 7:46 am
Has thanked: 2 times
Been thanked: 1 time

Re: Strange behavior LILYGO T-Display ESP32

Post by waldli »

Hello,
Thanks Peter,
the information that the GPIO35 has no pull-up and pull-down resistors
was correct. With a 4k7 resistor everything works as planned.

Regards
Waldemar
User avatar
PeterN
Posts: 641
Joined: Mon Feb 08, 2021 7:56 pm
Location: Krefeld, Germany
Has thanked: 296 times
Been thanked: 357 times
Contact:

Re: Strange behavior LILYGO T-Display ESP32

Post by PeterN »

Hi Waldemar,

prima, dass es nun grundsätzlich klappt!
Francesco hat aber auch recht mit seinem Hinweis auf das Prellen.
Ich würde in der Interruptroutine noch zu Beginn 100ms warten und nur weitermachen, wenn der Pin danach noch heruntergezogen ist. Sonst RETURN


great that it's basically working now!
Francesco is also right with his reference to bouncing.
I would wait 100ms in the interrupt routine at the beginning and only continue if the pin is still pulled down afterwards. Otherwise RETURN
Post Reply