NHD-0420CW-AY3 and 5 V Power Supply

hodoe

• April 02, 2021 06:06

Hello, I have a question of understanding. I bought this excellent oled NHD-0420CW-AY3 and I do not understand the 5 V power supply.

1. Hardware:

The following makes no difference:
- 5 V at V_DD and REGV_DD
- 5 V only at V_DD
- 5 V only at REGV_DD

Which is correct?


2. Software:

The initialization routine:

void init(){

     RES = 1;//reset HIGH - inactive
     delayms(1);//delay
     command(0x2A);//function set (extended command set)
     command(0x71);//function selection A
     data(0x00);//disable internal VDD regulator (2.8V I/O). data(0x5C) = enable regulator (5V I/O)

If I send only data(0x00) or data(0x5C). It makes no difference.

Which is correct?


Thanks in advance.

Holger

0

• 

  Zach P

  NHD Staff

  • April 06, 2021 11:23

  Hello Holger,
  
  When running at 5V there is an internal connection (between Vdd & REGVdd) happening that over rides the software for the internal regulator. Only when applying around the 3V does the software regulator take into effect and needed. When working with 5V it is recommended to output to both Vdd and REGVdd (not just one).
  
  Thanks,
  
  ZP

  0
• 

  hodoe

  • April 07, 2021 07:46

  Dear ZP, thank you very much!
  
  So with +5 V on both Vdd and REGVdd  this code is not required.
  
  command(0x2A); //function set (extended command set)
  command(0x71); //function selection A
  data(0x00); // disable internal VDD regulator (2.8V I/O). data(0x5C) = enable regulator (5V I/O)
  
  I tested it.
  
  
  best regards
  Holger

  0

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