Problem with SSD1306 LCD and U8glib

Perhaps something else is wrong with it. Perhaps it is broken. Sorry, but I don't know what else you could do.

Maybe you can post a picture of your setup to verify your wiring.

Oliver

Hello,
here are 2 pictures. Not the best quality, but I think it should be enough...

Wiring seems okay.

Yes.
Do you know what I can do, to test if it's broken? Using a multimeter or something?

hmm... i am also running out of ideas... In those cases i usually start to use my scope to observere activity on the signal and clock lines.

Oliver

My best advice at this point it to forget that display.
Buy a better display from a good company that sells electronics which work: Monochrome 0.96 128x64 OLED Graphic Display - STEMMA QT : ID 326 : $17.50 : Adafruit Industries, Unique & fun DIY electronics and kits

Hello,
I just wanted to tell you, that the module is working now.
I wrote to the chinese seller, and he sent me a link to a chinese website with a working library and code: 14blog.com
Google-translate does hard work on this page :wink:

BTW the module doesn't need any resistors, and it works on every digital pin.

Thanks for help!

Regards.

@ Oliver:

Can you please take a look at the library and check if the module works also with u8glib?
The provided library is really "buggy".

Thanks for the feedback. Main problem is, that i do not own this display. So i can not do any tests on it.

Oliver

olikraus:
Thanks for the feedback. Main problem is, that i do not own this display. So i can not do any tests on it.

Oliver

OK. Thanks anyway!

I have ordered the same display from this china seller. Usually it will take some weeks, but once it is here i will verify this.

Oliver

olikraus:
I have ordered the same display from this china seller. Usually it will take some weeks, but once it is here i will verify this.

Oliver

GREAT! :slight_smile: Thank you! Danke dir! :slight_smile:

Interesting.
So they use I2C without acknowledge, because SDA can not pull the line low, as I suspected.
But they use a library with software I2C that can be used on any pin ?
I clicked the download link, but did not get a file.

Caltoa:
Interesting.
So they use I2C without acknowledge, because SDA can not pull the line low, as I suspected.
But they use a library with software I2C that can be used on any pin ?
I clicked the download link, but did not get a file.

Yes, I2C can be used on any pin. I am too much a newbie for finding that interesting. :slight_smile:
I uploaded the rar-file to my box-account: Box

Still strange. The SSD1306 is a standard controller. According to the datasheet of the SSD1306, standard I2C should be fully supported. In fact U8glib has been reported to work fine with the Adafruit OLEDs (also based on SSD1306)

Oliver

Frantischek, thanks for the file !

olikraus, I read that SDA is split into two pins for reading and writing. The heltec display uses only the input pin. I have been reading about those heltec displays for my own heltec display (SPI without CS interface).

In the source of the rar archive they do "software I2C without ACK". I will wait for the display and do some deeper analysis.

Oliver

Hi

I have received the display. Indeed, it does not send the I2C ACK bit. I have updateded U8glib (see attached prerelease). Now U8glib works with this nice little display.

Oliver

Edit: U8glib constructor is (Arduino Uno only): U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_NO_ACK)

u8glib_arduino_v1.16pre1.zip (1.05 MB)

If it doesn't send that acknowledge bit, does it send any thing at all ?
This seems to be the same display (it is available in white, blue and blue/yellow) as fitted on the Crius CO-16.
Are pins 19 and 20 of the flex cable from the display connected ?
If not it can't send anything back and that can be solved by connecting these pins with a drop of solder, which is easy to do.
After that, the display will work as it's meant to be.