NHD-0220CW-AG3 Character set

OS

• March 28, 2017 02:49

Hello.
We are using a NHD-0220CW-AG3 (in 4-bit Parallel 6800 interface) with the character set of ROM C.
Is it possible to overwrite the first 8 character of ROM C to add individual character?

I tried it in this way, but did not succeed. I only got strange signs on the display.

void data_write (uchar c)
{//high byte
  PORTA = (c & 0xF0);
  DC_HIGH;
  RW_HIGH;
  E_HIGH;
  wait(LCD_WAIT);
  E_LOW; //data latched
 
  //low byte
  PORTA = (((c & 0x0F) << 4));
  DC_HIGH;
  RW_HIGH;
  E_HIGH;
  wait(LCD_WAIT);
  E_LOW; //data latched
}

void command (uchar c)
{//high byte
  PORTA = (c & 0xF0);
  DC_LOW;
  RW_LOW;
  E_HIGH;
  wait(LCD_WAIT);
  E_LOW; //data latched
 
  //low byte
  PORTA = (((c & 0x0F) << 4));
  DC_LOW;
  RW_LOW;
  E_HIGH;
  wait(LCD_WAIT);
  E_LOW; //data latched
}

set_newCharToFont(void)
{
  command(0x40); //0x40 -> pos of first char in CGRAM
  data_write(0x08); //1   8
  data_write(0x10); //2   10
  data_write(0x08); //3   8
  data_write(0x00); //4   0
  data_write(0x05); //5   5
  data_write(0x07); //6   7
  data_write(0x05); //7   5
  data_write(0x00); //8   0
}

void show_char(uchar num)
{
  command(0x01); //clear display
  command(0x02); //return home
  data(num); //1 -> Read data in ROM C at pos num
}


in main.c:

set_newCharToFont();
show_char(0);

One more question:
If we need more than 8 new character in the font, would it be possible to get a display with a customized software, which contains the needed characters?

Best regards,
OS

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• 

  OS

  • March 28, 2017 07:15

  Hi again.
  Luckily I found my mistake why I could not write data to CGRAM.
  In the function data_write() the RW signal was wrong, RW_HIGH should be RW_LOW.  
  
  
  Unfortunately we really need to set more than 8 individual characters, minimum 13 chars.
  
  Is there a possibility to get a display with a modified software (modified font set)?
  
  Best regards.
  OS

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• 

  Saurabh_B

  • March 28, 2017 09:19

  Hello,
  The Font Tables on our displays are defined by the manufacturers of the controllers, in this case it would be the company that manufactures the US2066 controller.
  
  The best solution for requiring multiple characters would be to use a graphic OLED display.
  However for this one you would need to create a font table as well.

  0

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