CFAL64128 OLED - Smearing or Ghosting on active lines

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cwolcott

New member
Hello, I have the 64x128 in-Cell Touchscreen Development Kit Part Number: CFAL64128B0-0096WC-E1-2
The display works fine but after a few power On/Off cycles during debug-development, there is a smearing / ghosting affect only on the lines that have active pixels turned on as shown here:

1698080801513.png


This seems to be a persistent (i.e damaged) artifact that will not go away. Could improper power cycling cause this? The data sheet says to enable Vcc after the initializing the display configuration registers. And also for power down. However, I don't see how I can control the Vcc supply separately from the rest of the supply voltages? How can I prevent this issue in the future with replacement OLEDs? Thanks!
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CF Kelsey

Administrator
Staff member
Are you using the demo code that came installed or have you changed it?

This issue does not go away even if you turn the display off for an extended time and reinitialize?

Does the streaking change if you change the displayed image? (e.g., if all black is displayed are the white lines still visible?)
 
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cwolcott

New member
Hi CF Kelsey. Yes, using the demo code in that picture. However, I did hookup the display to my own target for development using the same signals as the demo setup. Didn't see these streaks until sometime later while doing my own display elements. I put the display back on the Arduino-clone board with the original demo code but the steaks remained.

The streaks stay and are persistent even after days of the display not being turned on - that's why I think it's damaged.

An all-black display only shows the streaking on the very top, length-wise, edge for one or two lines. If, say, I draw a single character in the middle of the screen, then the streak only appears on the lines that the letter appears on from the very left to the very right of the display. Everywhere else it's black. It's like whatever row has an active pixel on it, the whole row lights up but dimmer than the active pixel.

How important is the startup sequence for not enabling Vcc until after the configuration registers are setup? The only difference in the setup configuration I'm making is setting the Segment Remap from 0xA1 to 0xA0. Everything else is the same as the demo code. Thanks.
 
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CF Kelsey

Administrator
Staff member
We haven't seen this type of streaking happen before. If you fill out our RMA form, we'll get a replacement shipped to you. Just include a link to here in the explanation.

I'm doing a bit more research on what could have caused it. It certainly seems like a damaged controller which could be caused by ESD or usage outside of the electrical characteristics in the datasheet. I'd be surprised if it is because of Vcc being applied too early, especially because you're using our board and initialization sequence.
 
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