ssd1306 Controlled Heltec Oled 128x64 SPI

Using Arduino Displays
#1

Hi

i’m working on this Oled driver.

when i initialized the screen , many of random dots appears on screen.

how can i reset these dots?

i have got Two lcd but result is same ( many of non-controlled dots)

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#2

Hi, welcome to the forum.

We can't tell what is wrong, because we have to know what you have and what you are doing.
You have a heltec display with SPI. Can you make a photo of it ? or give a link to it ?
Which Arduino board are you using, and how is the display connected ?

Which library are you using ? I suppose the U8Glib ?

#3

The dots could be caused by random values in the screens memory . A clear screen command should fix this.

Do you have a datasheet of the Screen?
Can you post it?

#4

i’m writing own library for this screen.

The oled panel connected to spi interface of arduino uno ( SCK 13, MOSI 11, CS 10, DC 9 )

there are no datasheet from “heltec”, i have got only “SSD1306 datasheet”.

// inslude the SPI library:
#include <SPI.h>
const int OledCS= 10;
const int OledDC= 9;
 
int Data[1024];

void OLED_command(int com) 
{ 
     digitalWrite(OledCS,LOW);
     digitalWrite(OledDC,LOW); 
       delay(1);
     SPI.transfer(com);      
     digitalWrite(OledCS,HIGH);
} 


void  OLED_init() 
{ 
   OLED_command ( 0xAE) ;  //DisplayOFF
   OLED_command ( 0xa8); 
   OLED_command ( 0x3f); 
   OLED_command ( 0xd3); 
   OLED_command ( 0x00); 
   OLED_command ( 0x40); 
    
   OLED_command ( 0xa0); //0--127 Segment
   OLED_command ( 0xc0); 
       
   OLED_command ( 0xda); 
   OLED_command ( 0x02); // 12h
   OLED_command ( 0x81); //Contrast Command
   OLED_command ( 0x7F); //Contrast Data
   OLED_command ( 0xa4);  //Display Entire On
   OLED_command ( 0xA6) ; // A6 nomal A7 Invert
   OLED_command ( 0xd5); 
   OLED_command ( 0x80); 
   
   OLED_command ( 0x8d); 
   OLED_command ( 0x14) ; 
   OLED_command ( 0xAF) ;  
   
} 


void OLED_write() 
{ 
 
   OLED_command ( 0x21) ; //Column Adresi Belirle
   OLED_command ( 0); 
   OLED_command ( 127); 
   OLED_command ( 0x22) ; //Page Adresi Belirle
   OLED_command ( 0); 
   OLED_command ( 7); 
   
   OLED_command(0x40) ;
   
   digitalWrite(OledDC,HIGH); 
 delay(2);
   for (int i = 0; i < 1024; i++)    { 
     SPI.transfer(      Data[i]);     
      
   }    
     digitalWrite(OledCS,HIGH); 
} 

void setup() {
  // set the slaveSelectPin as an output:
  pinMode (OledCS, OUTPUT);
  pinMode (OledDC, OUTPUT);
 
  // initialize SPI:
  SPI.begin(); 
   
  SPI.setDataMode(SPI_MODE0);
  SPI.setClockDivider(SPI_CLOCK_DIV32);
 
  OLED_init();
}

int data , index;
void loop() {
 
  OLED_write();
  
  Data[index++] = data++;
 
  if(index>1024) index = 0;
  if(data>255) data = 0;
   delay(100);
  
}

this is My Test Code.

#5

That is a SPI interface, without reset pin.

Why do you want to write your own library ? It could take months. Someone else has already done that for you.

#6

I recently wrote a very simple and small library for SSD1306 (and SH1106) displays, mostly for displaying text. Not the final version, but it might help you along. Do mind: I use some macros for setting CS and DC (and RST), it saves 25% on time compared to using variables for setting the pins. You already have the datasheet for the driver, you will need it if you go over my code.

I like to understand all of my code, it's a bit of a sport, so I write libraries for most things I use, just for the fun of it.

Cheers,

Jack

#7