File content as of revision 136:53a83b91854c:

#include "mbed.h"
#include "Adafruit_SSD1306.h"

#define ADT7420_TEMP_REG (0x00)
#define ADT7420_CONF_REG (0x03)
#define EVAL_ADT7420_ADDR (0x48)

I2C i2c(I2C_SDA, I2C_SCL);
RawSerial pc(PA_2, PA_3, 115200);


Adafruit_SSD1306_SPI goled(D11, D13, D10, D4, D7, 64, 128);

int main() {
 
    int status;
    float temp;
    char data_write[2];
    char data_read[2];
    
    i2c.frequency(100000);
    data_write[0] = ADT7420_CONF_REG;
    data_write[1] = 0x40;
    status = i2c.write((EVAL_ADT7420_ADDR<<1), data_write, 2);
    if(status!=0) {
        pc.printf("I2C configuration error!\r\n");
        while(1){
        }
    }
    goled.clearDisplay();
    goled.splash();
    ThisThread::sleep_for(3000);
    goled.clearDisplay();
    
    goled.setTextSize(2);
    goled.printf("OLED Lab.\r\n");
    goled.setTextSize(1);
    goled.printf("HGU in Pohang \r\n\r\n");
    
    int16_t cursor_x = goled.cursor_x;
    int16_t cursor_y = goled.cursor_y;
    
    while(1) {
        
        goled.setTextCursor(cursor_x,cursor_y);
        
        data_write[0] = ADT7420_TEMP_REG;
        i2c.write((EVAL_ADT7420_ADDR<<1),data_write,1,0);
        i2c.read((EVAL_ADT7420_ADDR<<1 | 0x01), data_read, 2, 0);
        
        int tempval = ((int) data_read[0]<<8 | data_read[1]);
        tempval >>= 3;
        if((tempval & 0x1000) > 0) {
            temp = (tempval - 8192)/16.0;
        } else {
            temp = tempval/16.0;
        }
        
        pc.printf("Temperature: %0.4f\r\n", temp);
        goled.printf("Temperature: %0.4f\r\n", temp);
        goled.display();
        
        ThisThread::sleep_for(1000);
    }
}