Problem with WHITE COLOR CHAR on NHD-0440WH-ATMI-JT with 2 lines

Mic71

• November 04, 2018 08:07

Dear ALL, I bought a LCD NHD-0440WH-ATMI-JT and I make the firmware on STM32 but I found a problem with WHITE color. This is my problem: when I enable two lines I not see the white color char but a blue with constrast loss . If disable two lines I see one line with WHITE color.... How I can see two lines with WHITE color char?

Thanks in advance

Michele

This my init code with TWO LINES.... Where I wrong?

LCD_SetCommandPin4bit(0,0,1,1); // send 0011 : 0x30
     LCD_PulseEnable(iEx);
     DWT_Delay_us(5);

     LCD_SetCommandPin4bit(0,0,1,1); // re-send 0011 : 0x30
     LCD_PulseEnable(iEx);
     DWT_Delay_us(5);
 
     LCD_SetCommandPin4bit(0,0,1,1); // re-send 0011 : 0x30
     LCD_PulseEnable(iEx);
     DWT_Delay_us(5);
     
     LCD_SetCommandPin4bit(0,0,1,1); // ...setting 8 bit...
     LCD_PulseEnable(iEx);
     
     LCD_SetCommandPin8bit(0,0,1,1,1,0,0,0); // send 0011 1000 : 0x38 Function Set = 8bit mode; 2-line; 5x8
     LCD_PulseEnable(iEx);
     
     LCD_SetCommandPin8bit(0,0,0,0,1,0,0,0); // send 0000 1000 : 0x8 Turn off display
     LCD_PulseEnable(iEx);
   
     LCD_SetCommandPin8bit(0,0,0,0,1,1,1,1); // send 0000 1100 : 0xC Turn on display; cursor blink
     LCD_PulseEnable(iEx);

     LCD_SetCommandPin8bit(0,0,0,0,0,0,0,1); // send 0000 0001 : 0x1 Clear
     LCD_PulseEnable(iEx);

     LCD_SetCommandPin8bit(0,0,0,0,0,1,1,0); // send 0000 0110 : 0x6 Entry mode set
     LCD_PulseEnable(iEx);

 

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• 

  Alee_S

  • November 21, 2018 08:07

  Hi Michele,
  
  The code you have shown looks good to me.
  
  It could be possible that Pin 12 may not be receiving enough contrast voltage to display correctly, hence you are seeing blue with a contrast loss under 2-line mode.
  
  How are you currently connecting Pin 12 of the display? Are you using fixed resistors, or a potentiometer?
  Also, what is your measured voltage reading on Pin 12 of the display?

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