2.7" OLED Kit Ghosting Issues

[apcesarz]

Hi, I just received the 2.7" OLED graphic display kit (part of order #1489638 from July 9). After assembling & wiring it according to the Adafruit tutorial (https://learn.adafruit.com/2-7-monochro ... lay-module), the display exhibits odd behavior when running the SSD1325test program included in the library. When a large amount of information is shown on the screen, the graphics become distorted and unstable. I've checked all the cable connections and solder joints, and they all seem to be solid.

I noticed that my kit shipped with a CD4050 level shifter instead of the HC4050 level shifter specified in the item description of the OLED kit, and after spending time reading about similar issues on the forums, this seemed to be the cause of their problem.

I've attached an image of the wiring setup with the display exhibiting the aforementioned ghosting issue. Hope you can help! Thanks.

[adafruit_support_rick]

Soldering looks good. Could be the level shifter. Could also be a bad jumper or breadboard socket.

Can you try some different jumpers and breadboard sockets? If that doesn't help, email [email protected] with a link to this post for a replacement chip

[apcesarz]

Hello! I'm back with an update.

After trying different jumpers and breadboard sockets to no avail, support sent me a replacement CD4050 level shifter chip. I hooked everything up according to the wiring & setup directions as before with the replacement level shifter chip, and the problem persists. Here's a video of the display operating with the chip I just received:

https://www.youtube.com/watch?v=uVbVTcL7Q-w

Any ideas as to the next step?

[adafruit_support_rick]

Rats. Well, everything else looks good, so it must be the display itself. Please email [email protected] with a link to this post for a replacement . Thanks for your patience.

[apcesarz]

Progress update -

I received the replacement OLED kit and wired everything up. The identical problem ocurred. I acquired an Adafruit 4-channel I2C-safe bi-directional logic level converter and wired all data pins (except pin no. 15 due to only 4 channels on the adafruit level shifter - this one is being run through the CD4050 level shifter chip), and the issues went away (on both of the OLED screens - see photos). Based on this experiment, it would seem that the CD4050 level shifter chip is an incompatible model for running this particular screen off a 5v logic device.

Do you have any recommendations for a level shifter chip that supports the 5 channels required for this display?

[adafruit_support_rick]

Although there are some forums threads on this, we've actually seen very few problems like this with the level shifter chips that ship with these displays. Maybe you could try moving things around on your breadboard a bit. Try some different jumper wires as well.

The 74AHCT125 might work for you. It's a quad buffer, so you would either need two of them, or you could use just one in conjunction with the CD4050 you already have.
https://www.adafruit.com/product/1787