NHD-0420D3Z-FL-GBW-V3 not displaying characters

T3Mentor

• February 03, 2017 09:07

I am using a NHD-0420D3Z-FL-GBW-V3 in the SPI mode to interface to an Arduino Uno.  Every time I write to the display, all the pixels in a character are illuminated,  as if is sent FF, rather than the actual 31 (1) that I was using to test my set up.  I have the baud rate set at 9600 (yes, slow I know, but I'm just testing at this point ) , MSBFIRST, and SPIMODE3.   I'm not sure what's going on here, any advice? 

0

• 

  Saurabh_B

  • February 13, 2017 09:07

  Hello,
  
  I have attached my SPI Code for this display using an Arduino:

  //---------------------------------------------------------
  /*
  SPI Code.c
  Program for writing to Newhaven Display Serial LCD Character Displays via SPI.
  
  (c)2016 Saurabh Baxi - Newhaven Display International, LLC.
  
          This program is free software; you can redistribute it and/or modify
          it under the terms of the GNU General Public License as published by
          the Free Software Foundation; either version 2 of the License, or
          (at your option) any later version.
  
          This program is distributed in the hope that it will be useful,
          but WITHOUT ANY WARRANTY; without even the implied warranty of
          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
          GNU General Public License for more details.
  */
  //---------------------------------------------------------
  
  
  // DEFINITIONS
  #define SCLK  8
  #define  SPIS  9
  #define SDO   10
  
  const char slave = 0x7E;
  const char comsend = 0x00;
  const char datasend = 0x40;
  
  char const t1[]=(" Newhaven  Display  ");
  char const t2[]=("=SERIAL==Peripheral=");
  char const t3[]=("=====Interface======");
  char const t4[]=("=ARDUINO=====TESTER=");
  //Basic Functions/////////////////////////////
  void spiout(unsigned char a){
    int n;
    unsigned char d;
    d = a;
    digitalWrite(SPIS,LOW);
    for(n =0; n<8; n++){
      delayMicroseconds(20);
      if((d&0x80)==0x80)
        digitalWrite(SDO, HIGH);
      else
        digitalWrite(SDO, LOW);
      d = (d<<1);
      digitalWrite(SCLK, LOW);
      delayMicroseconds(20);
      digitalWrite(SCLK, HIGH);
    }
    digitalWrite(SPIS, HIGH);
  }
  void disp(const char *text){
    int n;
    for (n = 0; n <20 ; n++){
      spiout(*text);
      text++;
      delay(10);
    }
  }
  
  void setup() {
    pinMode(SPIS, OUTPUT);
    pinMode(SDO, OUTPUT);
    pinMode(SCLK, OUTPUT);
    digitalWrite(SCLK, LOW);
    digitalWrite(SDO, LOW);
    digitalWrite(SPIS, HIGH);
    delay(10);
    spiout(0xFE);
    spiout(0x51);   //Clear Screen
    delay(10);
    spiout(0xFE);
    spiout(0x46);   //Cursor Home
    delay(5);
    spiout(0xFE);
    spiout(0x47);   // Underline cursor
    delay(5);
    spiout(0xFE);
    spiout(0x53);   // Set backlight Brightness
    spiout(8);   // Value
    delay(2);
    spiout(0xFE);
    spiout(0x52);   // Set Contrast
    spiout(40);   // Value
  }
  
  void loop() {
    int i;
    spiout(0xFE);
    spiout(0x46);   // Cursor Home
    delay(10);
    disp(t1);    // Display T1
    delay(5);
    spiout(0xFE);   
    spiout(0x45);   // Set Curser Address
    spiout(0x40);   // Line 2
    delay(5);
    disp(t2);
    spiout(0xFE);   
    spiout(0x45);
    spiout(0x14);   // Line 3
    delay(5);
    disp(t3);
    spiout(0xFE);
    spiout(0x45);
    spiout(0x54);   // Line 4
    delay(5);
    disp(t4);
    spiout(0xFE);
    spiout(0x49);   // Move cursor left 1 place
   while(1);    // Wait here
  }

  Would you be able to send a picture of what you are seeing?

  0

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