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re:GC9A01 Round LCD with ESP32 & Arduino

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Eminent Member
Joined: 11 months ago
Posts: 16
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Hi folks,

In the DBWS video around 29:20 Bill points out an artifact where the inner ring of numbers is erased as the dial moves.

I can duplicate the examples. But for me in the animated dial example when the inner ring is erased I get blocks of white pixels.

When I read from the GC9A01 I get f's. I suspect there is a pull up on my board that is not in the demo version. But it could be other things.

Bodmer (TFT_eSPI, author) mentions that his round display possibly has config pins that do not allow bi-direction data on the SDA pin.

I've duplicated this on my Uno and LOLIN ESP D32-Pro, with the waveshare display and a no-name version from alibaba.

I was wondering if anyone has been able to read from the GC9A01 ? If you've got it to work could you share your hardware?

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Illustrious Member
Joined: 3 years ago
Posts: 4801

I haven't 'played' with this device yet, but did notice when searching for sources that there seemed to be a few possibly different boards out there. Bill points out two of them in the video but I 'think' I saw even more. Or not 😀 

Arduino says and I agree, in general, the const keyword is preferred for defining constants and should be used instead of #define
"Never wrestle with a pig....the pig loves it and you end up covered in mud..." anon
My experience hours are >75,000 and I stopped counting in 2004.
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