Display Update 2.7"

[JeanPaul]

Hello,

I'm trying to use a 2.7" EPD to show a voltage value. The refresh rate is about 1 Hz. I'm not sure if it’s the right job for this EPD or I'm doing something wrong with partial update, but I'm not getting a good result (ghosting) like some videos on internet.
 
https://www.youtube.com/watch?v=0jLfi62LT08
https://www.youtube.com/watch?v=AMvEiRYjxRw

I'm following the steps of this comment:

https://github.com/repaper/gratis/issues/19

Is there another way to make partial updates and deal with ghosting?

Thanks.

[JeanPaul]

I uploaded a video to help to understand.

https://youtu.be/Wgs8EoVNa0I

Thanks.

[Charming]

Hello Jean Paul,

Thanks for taking the video to us for better understanding your question.
1Hz=1000ms which is ok for the partial update. (can be shorter. ex, 500ms)
Your partial update waveform looks correct. I have sent you the sample code via email with an application note. Please check again with the guide and sample source. Let me know if the ghosting remains.

Charming Su @ PDi-FAE

[JeanPaul]

Hello Charming Su,

Thanks for the sample code.
It helped a lot.

But some questions remain :

1. Should I turn off EPD between each update or it's okay to keep it energized for a long period ?

2. In the code sent , what is the purpose of ( / * set scan line off ( extra arrangement for partial update)) ? After send all data and scan byte the data is resent and scan byte is left zero ?

Thanks for your attention and quick answer.
I'm getting better results but still not so good as the internet videos.

Jean Paul

[Charming]

Hi Jean Paul,

1. [Q1] Should I turn off EPD between each update or it's okay to keep it energized for a long period ?
   [A1] It's okay you keep the display energized for a long period, just the COG keeps consuming few energy that less than display refreshing.
   Please do not run the power on stage again. You will just need to send next image pattern.
   
2. [Q2] In the code sent , what is the purpose of ( / * set scan line off ( extra arrangement for partial update)) ? After send all data and scan byte the data is resent and scan byte is left zero ?
   [A2] This comment was described in the Partial update code for G2 COG only. The G2 COG doesn't reset the scan lines to default level. Without this code snippet, your partial update still works. There will have decay phenomenon at the edge of horizontal lines after serval partial updates without changing the pixel data. I am attaching the effect for your reference. The code snippet is to resolve this issue.
   

Charming Su @ PDi-FAE