NHD-0420DZW-AG5 OLED character module--Displaying junk data

control3

• December 07, 2016 03:59

Hi,

We are using NHD-0420DZW-AG5 OLED character module for displaying system status and fault information.  We are using Serial interface for communication. Some times the data is getting corrupted and displaying some unintended data at unintended locations. This problem has been observed when the display is mounted above a SMPS where as it is not happened in other case. The data on the serial bus may be getting corrupted while transferring due to the induced/radiated noise from the SMPS.

Is there any recommendation for  pull up / pull down resistors  or capacitors on the serial interface lines to avoid the data corruption?
There is an inductive device L1 on the back side of the display. Can the induced noise in this device cause the data corruption?

Please suggest us to address this problem.

Thanks in advance,
Spandana

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  Paul_B

  • December 07, 2016 08:30

  Morning Spandana,
  
  When designing a display into your system, the first thing to consider is what components in the system are generating noise that the display might pick up. It is important that the system rails and ground be as noise free as possible. At the system level, utilize a star topology ground design connected to chassis ground or earth ground, if available.
  
  Below are a few tips that should help improve your design and eliminate / minimize the corrupt data you are experiencing:
  
  

  • Utilize EMI shielding foils and film
  • Place 33 Ohm resistors in series on the serial interface lines to help improve EMI performance

  
  Shielding techniques can go a long way toward reducing electromagnetic/RF interference (EMI) and delivering reliable systems.
  
  Hope this helps, feel free to contact me if you have any questions or concerns.

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  control3

  • December 11, 2016 23:19

  Hi Paul,
  Thanks for your reply.
  
  We will try to make use of your suggestions to improve our design further.
  
  Thanks,
  Spandana

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