NHD-C12864KGZ-FSW-GBW Readability problem

Tony

• March 27, 2014 08:07

Hello,

I am using the above LCD in one of our prototypes. The short cable on this LCD doesn't allow us to install it in the enclosure we have so I made a small PCB with two FFC connectors to be able to extend it. When I plug in the LCD direct to the main board it works perfectly. When I plug it into my extender board with a 5" FFC cable I can see the text but it is faint and doesn't have the contrast like when it is plugged in direct. I checked 3.3V thinking it may have dropped due to the added cable length and connections but it is fine. All the connections are ok between the main board and the 2nd FFC on the extender board. Are there any suggestions for what I could check or a particular issue that would cause the display to still work but be faint? Or are there any other issues using this cable extension approach that would make this not possible?

Thanks,
Tony

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  Michael_L

  • March 27, 2014 10:07

  You say the display works perfectly when plugged into the main board?  There may be an overlooked weak/loose connection somewhere on the extension board, or you may simply need to adjust the Electronic Volume command in your software to compensate for the "extended" setup.  Have you tried increasing/decreasing the value you are using with this command?  The command can be seen in the table of the controller's datasheet (page 50), here: https://newhavendisplay.com/content/app_notes/ST7565R.pdf
  More details about the Electronic Volume command can be seen on pages 45 & 46.

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  Tony

  • March 27, 2014 12:07

  It was a soldering issue on my FFC connector. I really appreciate your lightning fast response!
  Tony

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  Michael_L

  • March 28, 2014 12:07

  No problem!  How's that for lightning fast! :)

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