GC9A01 module and back light brightness

[Makuna]

I am using this module GC9A01 round IPS display module from AliExpress.
I have connected it to Arduino Mega 2560 using the 3.3v to the VCC. It basically works but I see flash when the brightness is normal and then it is faded and even goes darker toward the bottom of the screen.
I do have the BLK wire connected, but I went ahead and disconnected (the default is black light on) and displays the same.
Anyone have experience with one of these have some insights?

[moononournation]

try add 2.2k resistor in the middle of signal pins like this: https://youtu.be/-xrbyeakgBQ 「Michael Miller <[email protected]>」在 2021年2月24日週三，07:46 寫道：

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I am using this module GC9A01 round IPS display module from AliExpress <https://www.aliexpress.com/item/1005001322032932.html?aff_platform=true&aff_short_key=UneMJZVf&isdl=y&src=bing&albch=shopping&acnt=42005546&isdl=y&aff_short_key=UneMJZVf&albcp=373871275&albag=1308419064071836&slnk=&trgt=pla-4585375808811125&plac=&crea=81776241344382&netw=o&device=c&mtctp=e&utm_source=Bing&utm_medium=shopping&utm_campaign=PA_Bing_customlabel1_US_PC&utm_content=customlabel1%3D7&utm_term=gc9a01&msclkid=37fa195f23ec14778e88796aa00c8580> . I have connected it to Arduino Mega 2560 using the 3.3v to the VCC. It basically works but I see flash when the brightness is normal and then it faded and even goes dark toward the bottom of the screen. I do have the BLK wire connected, but I went ahead and disconnected (the default is black light on) and displays the same. Anyone have experience with one of these have some insights? — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#31>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADE5WWZ4CVSQBVAZTXSD53LTAQ43TANCNFSM4YDNS4YA> .

[Makuna]

That fixed it!
So the pins are not 5v tolerant and cause this strange side effect.

[moononournation]

yes, same as ILI9341 「Michael Miller <[email protected]>」在 2021年2月24日週三，08:04 寫道：

…

That fixed it! So the pins are not 5v tolerant and cause this strange side effect. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#31 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADE5WW2JCC23QQODBDWDVYTTAQ67JANCNFSM4YDNS4YA> .

[tcerdaj]

My greatest respect to you and thanks for sharing such valuable information in this forum. I am currently trying to configure the wiring for Arduino Mega using the GC9A01 module, if possible could you share the diagram, please? Thank you.

I am trying https://www.waveshare.com/wiki/1.28inch_LCD_Module documentation, but they only have it for Arduino uno.

[moononournation]

As mentioned in instructables, ILI9341 and GC9A01 require extra effort for 5V MCU. It is recommended using 3.3V MCU for this display.