Column of characters not displaying.
I'm using the NHD‐0420CW‐AB3 and I'm having an issue with the display and I want to see if it's something I accidentally programmed or if it's a hardware issue. The eight column in each row cannot be printed to. When I attempt to push a character to that position the display freaks out.
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Hello Carl,
I actually have some example code I can share with you. It is written for the Arduino Mega. See below:#include <Wire.h>
//#include <SPI.h>
int RS = 30;
int E = 31;
int RES = 32;
int CS = 33;
int ASDA = 20;
int ASCL = 21;
int SCLK = 52;
int SDIN = 51;
int SDOUT = 50;
// R/W signal tied LOW (always write)
unsigned char tx_packet[]={0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
const char slave2w = 0x3C; //3C or 78
unsigned char mode = 0; // 0 = 8-bit parallel 6800 mode; 1 = i2c mode; 2 = SPI mode;
unsigned char text1[] = {"Newhaven Display----"};
unsigned char text2[] = {"Test----------------"};
unsigned char text3[] = {"16/20 Characters----"};
unsigned char text4[] = {"!@#$%^&*()_+{}[]<>?~"};
void command(unsigned char c)
{
unsigned char i, temp;
switch(mode)
{
case 0: digitalWrite(CS, LOW);
PORTA = c;
digitalWrite(RS, LOW);
digitalWrite(E, HIGH);
delay(1);
digitalWrite(E, LOW);
digitalWrite(CS, HIGH);
break;
case 1: tx_packet[0] = 0x00;
tx_packet[1] = c;
send_packet(2);
break;
case 2:
temp = 0xF8;
for(i=0;i<8;i++)
{
digitalWrite(SCLK, LOW);
if((temp&0x80)>>7==1)
{
digitalWrite(SDIN, HIGH);
}
else
{
digitalWrite(SDIN, LOW);
}
temp = temp << 1;
digitalWrite(SCLK, HIGH);
}
for(i=0;i<4;i++)
{
digitalWrite(SCLK, LOW);
if((c&0x01)==1)
{
digitalWrite(SDIN, HIGH);
}
else
{
digitalWrite(SDIN, LOW);
}
c = c >> 1;
digitalWrite(SCLK, HIGH);
}
for(i=0;i<4;i++)
{
digitalWrite(SCLK, LOW);
digitalWrite(SDIN, LOW);
digitalWrite(SCLK, HIGH);
}
for(i=0;i<4;i++)
{
digitalWrite(SCLK, LOW);
if((c&0x1)==0x1) // <------- Change
{
digitalWrite(SDIN, HIGH);
}
else
{
digitalWrite(SDIN, LOW);
}
c = c >> 1;
digitalWrite(SCLK, HIGH);
}
for(i=0;i<4;i++)
{
digitalWrite(SCLK, LOW);
digitalWrite(SDIN, LOW);
digitalWrite(SCLK, HIGH);
}
break;
}
}
void data(unsigned char d)
{
unsigned char i, temp;
switch(mode)
{
case 0: digitalWrite(CS, LOW);
PORTA = d;
digitalWrite(RS, HIGH);
digitalWrite(E, HIGH);
delay(1);
digitalWrite(E, LOW);
digitalWrite(CS, HIGH);
break;
case 1: tx_packet[0] = 0x40;
tx_packet[1] = d;
send_packet(2);
break;
case 2:
temp = 0xFA;
for(i=0;i<8;i++)
{
digitalWrite(SCLK, LOW);
if((temp&0x80)>>7==1)
{
digitalWrite(SDIN, HIGH);
}
else
{
digitalWrite(SDIN, LOW);
}
temp = temp << 1;
digitalWrite(SCLK, HIGH);
}
for(i=0;i<4;i++)
{
digitalWrite(SCLK, LOW);
if((d&0x01)==1)
{
digitalWrite(SDIN, HIGH);
}
else
{
digitalWrite(SDIN, LOW);
}
d = d >> 1;
digitalWrite(SCLK, HIGH);
}
for(i=0;i<4;i++)
{
digitalWrite(SCLK, LOW);
digitalWrite(SDIN, LOW);
digitalWrite(SCLK, HIGH);
}
for(i=0;i<4;i++)
{
digitalWrite(SCLK, LOW);
if((d&0x1)==0x1) // <------- Change
{
digitalWrite(SDIN, HIGH);
}
else
{
digitalWrite(SDIN, LOW);
}
d = d >> 1;
digitalWrite(SCLK, HIGH);
}
for(i=0;i<4;i++)
{
digitalWrite(SCLK, LOW);
digitalWrite(SDIN, LOW);
digitalWrite(SCLK, HIGH);
}
break;
}
}
void send_packet(unsigned char x)
{
unsigned char ix;
Wire.beginTransmission(slave2w);
for(ix=0;ix<x;ix++)
{
Wire.write(tx_packet[ix]);
}
Wire.endTransmission();
}
void output()
{
int i;
command(0x01);
delay(2);
for(i=0;i<20;i++){
data(text1[i]);
}
command(0xA0);
for(i=0;i<20;i++){
data(text2[i]);
}
command(0xC0);
for(i=0;i<20;i++){
data(text3[i]);
}
command(0xE0);
for(i=0;i<20;i++){
data(text4[i]);
}
delay(2000);
command(0x01);
delay(2);
for (i=0;i<20;i++){
data(text3[i]);
}
command(0xA0);
for (i=0;i<20;i++){
data(text4[i]);
}
command(0xC0);
for (i=0;i<20;i++){
data(text1[i]);
}
command(0xE0);
for (i=0;i<20;i++){
data(text2[i]);
}
}
void outputTest()
{
int i;
command(0x01);
delay(2);
data('N');
while(1);
for(i=0;i<20;i++){
data(text1[i]);
}
command(0xA0);
for(i=0;i<20;i++){
data(text2[i]);
}
command(0xC0);
for(i=0;i<20;i++){
data(text3[i]);
}
command(0xE0);
for(i=0;i<20;i++){
data(text4[i]);
}
delay(2000);
command(0x01);
delay(2);
for (i=0;i<20;i++){
data(text3[i]);
}
command(0xA0);
for (i=0;i<20;i++){
data(text4[i]);
}
command(0xC0);
for (i=0;i<20;i++){
data(text1[i]);
}
command(0xE0);
for (i=0;i<20;i++){
data(text2[i]);
}
}
void blocks()
{
int i;
command(0x01);
delay(2);
for(i=0;i<20;i++){
data(0x1F);
}
command(0xA0);
for(i=0;i<20;i++){
data(0x1F);
}
}
void setup()
{
pinMode(ASCL, OUTPUT); //set Arduino I2C lines as outputs
pinMode(ASDA, OUTPUT); //
digitalWrite(ASCL, LOW); //
digitalWrite(ASDA, LOW); //
pinMode(SCLK, OUTPUT);
pinMode(SDIN, OUTPUT);
pinMode(SDOUT, INPUT);
digitalWrite(SCLK, HIGH);
digitalWrite(SDIN, HIGH);
DDRA = 0xFF;
PORTA = 0x00;
DDRC = 0xFF;
PORTC = 0x00;
digitalWrite(RES, HIGH);
delay(10);
Wire.begin();
delay(10);
//SPI.begin();
command(0x2A); //function set (extended command set)
command(0x71); //function selection A, disable internal Vdd regualtor
data(0x00);
command(0x28); //function set (fundamental command set)
command(0x08); //display off, cursor off, blink off
command(0x2A); //function set (extended command set)
command(0x79); //OLED command set enabled
command(0xD5); //set display clock divide ratio/oscillator frequency
command(0x70); //set display clock divide ratio/oscillator frequency
command(0x78); //OLED command set disabled
command(0x09); //extended function set (4-lines)
command(0x06); //COM SEG direction
command(0x72); //function selection B, disable internal Vdd regualtor
data(0x00); //ROM CGRAM selection
command(0x2A); //function set (extended command set)
command(0x79); //OLED command set enabled
command(0xDA); //set SEG pins hardware configuration
command(0x10); //set SEG pins hardware configuration // <--------- Change
command(0xDC); //function selection C
command(0x00); //function selection C
command(0x81); //set contrast control
command(0x7F); //set contrast control
command(0xD9); //set phase length
command(0xF1); //set phase length
command(0xDB); //set VCOMH deselect level
command(0x40); //set VCOMH deselect level
command(0x78); //OLED command set disabled
command(0x28); //function set (fundamental command set)
command(0x01); //clear display
command(0x80); //set DDRAM address to 0x00
command(0x0C); //display ON
delay(100);
//Wire.begin();
//delay(10);
}
void loop()
{
while(1)
{
output();
//blocks();
while(1);
//outputTest();
delay(2000);
}
}Please verify your timing and initialization with what is listed in the example code, also can you tell me what interface you are using?
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