SSD1306 128x64 OLED display with TWI (I2C) text mode only

21.02.2017

Simple text mode library with 8pix height font.

Used:

128x64 pixel white OLED Display SSD1306 -4 pin connector for 2,47 € from:

https://www.aliexpress.com/item/1pcs-Free-Shipping-White-Blue-White-and-Blue-color-0-96-inch-128X64-OLED-Display-Module/32717950155.html

Aduino Nano 3.0 Clone for 2,10 € from:

https://www.aliexpress.com/item/1-unids-NANO-3-0-controlador-compatible-con-NANO-CH340-turno-USB-controlador-ninguna-CABLE-para/32418854222.html

2x 2k2 resistor

Breadboard

Schematic

Photo

Check connection and communication

#define  F_CPU 16000000UL
#include <avr/io.h>
#include <util/delay.h>
#include "My_uart.h"
#include "TWI.h"
#include <avr/interrupt.h>

int main(void)
{
    initUART();
    uart_println("TWI test");
    TWIInit();
    //check all address
    for (uint8_t i=0;i<128;i++)
        {   
                if(TWIcheckAdress(i<<1)) {
                uart_print("device found at 0x"); 
                uart_printh(i<<1);
                uart_putchar('\n');
                }   
        }
    uart_println("end ");
    while (1)
    {

    }
}

Download Atmel Studio 7.0 Project

twi2_scan.zip

SSD1306 initalization

void ssd1306_init(){
    
    // Init sequence for 128x64 OLED module
    ssd1306_command(SSD1306_DISPLAYOFF);                    // 0xAE

    ssd1306_command(SSD1306_SETDISPLAYCLOCKDIV);            // 0xD5
    ssd1306_command(0x80);                 // the suggested ratio 0x80
    
    ssd1306_command(SSD1306_SETMULTIPLEX);                  // 0xA8
    ssd1306_command(0x3F);
    
    ssd1306_command(SSD1306_SETDISPLAYOFFSET);              // 0xD3
    ssd1306_command(0x0);                                   // no offset
    
    ssd1306_command(SSD1306_SETSTARTLINE);                  // line #0
    
    ssd1306_command(SSD1306_CHARGEPUMP);                    // 0x8D
    ssd1306_command(0x14);          // using internal VCC
    
    ssd1306_command(SSD1306_MEMORYMODE);                    // 0x20/////
    ssd1306_command(0x00);          // 0x00 horizontal addressing
    
    ssd1306_command(SSD1306_SEGREMAP | 0x1); // rotate screen 180
    
    ssd1306_command(SSD1306_COMSCANDEC); // rotate screen 180
    
    ssd1306_command(SSD1306_SETCOMPINS);                    // 0xDA
    ssd1306_command(0x12);
    
    ssd1306_command(SSD1306_SETCONTRAST);                   // 0x81
    ssd1306_command(0xCF);
    
    ssd1306_command(SSD1306_SETPRECHARGE);                  // 0xd9
    ssd1306_command(0xF1);
    
    ssd1306_command(SSD1306_SETVCOMDETECT);                 // 0xDB
    ssd1306_command(0x40);
    
    ssd1306_command(SSD1306_DISPLAYALLON_RESUME);           // 0xA4
    
    ssd1306_command(SSD1306_NORMALDISPLAY);                 // 0xA6
    
    ssd1306_command(SSD1306_DISPLAYON);                     //switch on OLED
    
}

Display after initialization

Sample text output

#define  F_CPU 16000000UL
#include <avr/io.h>
#include <util/delay.h>
#include "My_uart.h"
#include "TWI.h"
#include <avr/interrupt.h>
#include "font.h"
#include "SSD1306.h"

int main(void)
{
    initUART();
    uart_println("TWI test");
    TWIInit();
    //check all address
    ssd1306_init();
    ssd1306_clear();
    
    for (uint8_t i=32; i<124;i++)
    {
        ssd1306_char(i);
    }
    
    ssd1306_print("                      SSD1306 OLED 128x64 Display  ");
    ssd1306_print("    Ketonk   2017  ;-)     ");
    for (uint8_t i=0; i<127;i++) ssd1306_data(0b11000000);
    
    while (1)
    {

    }
}

Download project

twi2_sample_text.zip