Inkplate 6PLUS display shows smudged content and ghosting

TECHNICAL SUPPORT Inkplate
1

Customer:

My Inkplate 6PLUS display isn’t displaying my input nicely - it appears “smudged” like wet paper. What could be wrong?

Originally submitted via email support on 12 December 2023. Migrated to the forum for community visibility.

2

Customer:

The right part of the screen is not displaying correctly. I can also see old content that should be cleared. Any idea what’s causing this?

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3

Soldered Support:

This issue is typically associated with a loose ePaper connection. To fix it, reconnect the ePaper to the flat cable connector:

  1. Turn off Inkplate completely
  2. Locate the ePaper connector on the back
  3. Gently pull down on the latches which hold the cable in place
  4. Pull out the flat cable
  5. Place the flat cable back inside, making sure it’s all the way in
  6. Secure it back with the latches

Note: The flat cable connectors are delicate, but this is straightforward to do yourself. This can happen during shipping or after prolonged use.

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4

Customer:

Here’s something odd - when I open the serial console in VSCode, I get the smudged screen. As soon as I stop the serial monitor, everything is fine. Any idea why?

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5

Soldered Support:

Try using a different USB cable that can supply more current. Sometimes cheap USB cables don’t provide enough current, which can cause this issue.

6

Customer:

That doesn’t make a difference. I have two 6PLUS screens - one works almost flawlessly, the other has smudges. For both devices: as soon as I turn on the backlight, everything is smooth all the time with no extra lines or distortion. Without backlight, both have some issues during usage. Why does the backlight affect screen drawing quality?

Also, I’m using JPG images from an SD card that were transformed from PDF. These images are displayed in reverse on the screen - white becomes black, black becomes white. For now I work around this in the call like this:

display.drawJpegFromSd(buff,0,0,false,true)

But it doesn’t make sense why these are inverted in the first place.

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7

Soldered Support:

Different JPG files are encoded differently. Some require inverting to display correctly on Inkplate, while others don’t. This is why we have the invert setting. If all your images are produced by the same process, they’ll have the same encoding and the setting should remain constant.

The backlight affecting screen drawing quality is unusual and could indicate a current issue or a connection issue between the ePaper and main board. This needs further investigation.

8

Soldered Support:

Try adding this line before display.begin();:

display.setInkplatePowerMode(INKPLATE_USB_PWR_ONLY);

You’ll need the latest version of the library for this to compile. This was implemented as a workaround because some Inkplate 6PLUS panels differ.

9

Customer:

I already have that line in my code. Every power source produces the same result - PC, powerbank, power adapter, different cables - so this doesn’t seem to be related to power.

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10

Soldered Support:

The line must be called before display.begin();. In your code, it’s called after. Move this line up before display.begin(); and try again. This fixed the same issue on an Inkplate 6PLUS I was working on.

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