Wiring BMP280 to Arduino Uno
Eventually as reported here, it worked using this pinout:

VCC --&gt; 3.3V
GND --&gt; GND
SCK --&gt; A5
SDI --&gt; A4


And this code:

#include &lt;Wire.h&gt;

#define BME280_ADDRESS 0x76
unsigned long int hum_raw,temp_raw,pres_raw;
signed long int t_fine;

uint16_t dig_T1;
 int16_t dig_T2;
 int16_t dig_T3;
uint16_t dig_P1;
 int16_t dig_P2;
 int16_t dig_P3;
 int16_t dig_P4;
 int16_t dig_P5;
 int16_t dig_P6;
 int16_t dig_P7;
 int16_t dig_P8;
 int16_t dig_P9;
 int8_t  dig_H1;
 int16_t dig_H2;
 int8_t  dig_H3;
 int16_t dig_H4;
 int16_t dig_H5;
 int8_t  dig_H6;

void setup()
{
    uint8_t osrs_t = 1;             //Temperature oversampling x 1
    uint8_t osrs_p = 1;             //Pressure oversampling x 1
    uint8_t osrs_h = 1;             //Humidity oversampling x 1
    uint8_t mode = 3;               //Normal mode
    uint8_t t_sb = 5;               //Tstandby 1000ms
    uint8_t filter = 0;             //Filter off 
    uint8_t spi3w_en = 0;           //3-wire SPI Disable

    uint8_t ctrl_meas_reg = (osrs_t &lt;&lt; 5) | (osrs_p &lt;&lt; 2) | mode;
    uint8_t config_reg    = (t_sb &lt;&lt; 5) | (filter &lt;&lt; 2) | spi3w_en;
    uint8_t ctrl_hum_reg  = osrs_h;

    Serial.begin(9600);
    Wire.begin();

    writeReg(0xF2,ctrl_hum_reg);
    writeReg(0xF4,ctrl_meas_reg);
    writeReg(0xF5,config_reg);
    readTrim();                    //
}


void loop()
{
    double temp_act = 0.0, press_act = 0.0,hum_act=0.0;
    signed long int temp_cal;
    unsigned long int press_cal,hum_cal;

    readData();

    temp_cal = calibration_T(temp_raw);
    press_cal = calibration_P(pres_raw);
    hum_cal = calibration_H(hum_raw);
    temp_act = (double)temp_cal / 100.0;
    press_act = (double)press_cal / 100.0;
    hum_act = (double)hum_cal / 1024.0;
    Serial.print("TEMP : ");
    Serial.print(temp_act);
    Serial.print(" DegC  PRESS : ");
    Serial.print(press_act);
    Serial.print(" hPa  HUM : ");
    Serial.print(hum_act);
    Serial.println(" %");    

    delay(1000);
}
void readTrim()
{
    uint8_t data[32],i=0;                      // Fix 2014/04/06
    Wire.beginTransmission(BME280_ADDRESS);
    Wire.write(0x88);
    Wire.endTransmission();
    Wire.requestFrom(BME280_ADDRESS,24);       // Fix 2014/04/06
    while(Wire.available()){
        data[i] = Wire.read();
        i++;
    }

    Wire.beginTransmission(BME280_ADDRESS);    // Add 2014/04/06
    Wire.write(0xA1);                          // Add 2014/04/06
    Wire.endTransmission();                    // Add 2014/04/06
    Wire.requestFrom(BME280_ADDRESS,1);        // Add 2014/04/06
    data[i] = Wire.read();                     // Add 2014/04/06
    i++;                                       // Add 2014/04/06

    Wire.beginTransmission(BME280_ADDRESS);
    Wire.write(0xE1);
    Wire.endTransmission();
    Wire.requestFrom(BME280_ADDRESS,7);        // Fix 2014/04/06
    while(Wire.available()){
        data[i] = Wire.read();
        i++;    
    }
    dig_T1 = (data[1] &lt;&lt; 8) | data[0];
    dig_T2 = (data[3] &lt;&lt; 8) | data[2];
    dig_T3 = (data[5] &lt;&lt; 8) | data[4];
    dig_P1 = (data[7] &lt;&lt; 8) | data[6];
    dig_P2 = (data[9] &lt;&lt; 8) | data[8];
    dig_P3 = (data[11]&lt;&lt; 8) | data[10];
    dig_P4 = (data[13]&lt;&lt; 8) | data[12];
    dig_P5 = (data[15]&lt;&lt; 8) | data[14];
    dig_P6 = (data[17]&lt;&lt; 8) | data[16];
    dig_P7 = (data[19]&lt;&lt; 8) | data[18];
    dig_P8 = (data[21]&lt;&lt; 8) | data[20];
    dig_P9 = (data[23]&lt;&lt; 8) | data[22];
    dig_H1 = data[24];
    dig_H2 = (data[26]&lt;&lt; 8) | data[25];
    dig_H3 = data[27];
    dig_H4 = (data[28]&lt;&lt; 4) | (0x0F &amp; data[29]);
    dig_H5 = (data[30] &lt;&lt; 4) | ((data[29] &gt;&gt; 4) &amp; 0x0F); // Fix 2014/04/06
    dig_H6 = data[31];                                   // Fix 2014/04/06
}
void writeReg(uint8_t reg_address, uint8_t data)
{
    Wire.beginTransmission(BME280_ADDRESS);
    Wire.write(reg_address);
    Wire.write(data);
    Wire.endTransmission();    
}


void readData()
{
    int i = 0;
    uint32_t data[8];
    Wire.beginTransmission(BME280_ADDRESS);
    Wire.write(0xF7);
    Wire.endTransmission();
    Wire.requestFrom(BME280_ADDRESS,8);
    while(Wire.available()){
        data[i] = Wire.read();
        i++;
    }
    pres_raw = (data[0] &lt;&lt; 12) | (data[1] &lt;&lt; 4) | (data[2] &gt;&gt; 4);
    temp_raw = (data[3] &lt;&lt; 12) | (data[4] &lt;&lt; 4) | (data[5] &gt;&gt; 4);
    hum_raw  = (data[6] &lt;&lt; 8) | data[7];
}


signed long int calibration_T(signed long int adc_T)
{

    signed long int var1, var2, T;
    var1 = ((((adc_T &gt;&gt; 3) - ((signed long int)dig_T1&lt;&lt;1))) * ((signed long int)dig_T2)) &gt;&gt; 11;
    var2 = (((((adc_T &gt;&gt; 4) - ((signed long int)dig_T1)) * ((adc_T&gt;&gt;4) - ((signed long int)dig_T1))) &gt;&gt; 12) * ((signed long int)dig_T3)) &gt;&gt; 14;

    t_fine = var1 + var2;
    T = (t_fine * 5 + 128) &gt;&gt; 8;
    return T; 
}

unsigned long int calibration_P(signed long int adc_P)
{
    signed long int var1, var2;
    unsigned long int P;
    var1 = (((signed long int)t_fine)&gt;&gt;1) - (signed long int)64000;
    var2 = (((var1&gt;&gt;2) * (var1&gt;&gt;2)) &gt;&gt; 11) * ((signed long int)dig_P6);
    var2 = var2 + ((var1*((signed long int)dig_P5))&lt;&lt;1);
    var2 = (var2&gt;&gt;2)+(((signed long int)dig_P4)&lt;&lt;16);
    var1 = (((dig_P3 * (((var1&gt;&gt;2)*(var1&gt;&gt;2)) &gt;&gt; 13)) &gt;&gt;3) + ((((signed long int)dig_P2) * var1)&gt;&gt;1))&gt;&gt;18;
    var1 = ((((32768+var1))*((signed long int)dig_P1))&gt;&gt;15);
    if (var1 == 0)
    {
        return 0;
    }    
    P = (((unsigned long int)(((signed long int)1048576)-adc_P)-(var2&gt;&gt;12)))*3125;
    if(P&lt;0x80000000)
    {
       P = (P &lt;&lt; 1) / ((unsigned long int) var1);   
    }
    else
    {
        P = (P / (unsigned long int)var1) * 2;    
    }
    var1 = (((signed long int)dig_P9) * ((signed long int)(((P&gt;&gt;3) * (P&gt;&gt;3))&gt;&gt;13)))&gt;&gt;12;
    var2 = (((signed long int)(P&gt;&gt;2)) * ((signed long int)dig_P8))&gt;&gt;13;
    P = (unsigned long int)((signed long int)P + ((var1 + var2 + dig_P7) &gt;&gt; 4));
    return P;
}

unsigned long int calibration_H(signed long int adc_H)
{
    signed long int v_x1;

    v_x1 = (t_fine - ((signed long int)76800));
    v_x1 = (((((adc_H &lt;&lt; 14) -(((signed long int)dig_H4) &lt;&lt; 20) - (((signed long int)dig_H5) * v_x1)) + 
              ((signed long int)16384)) &gt;&gt; 15) * (((((((v_x1 * ((signed long int)dig_H6)) &gt;&gt; 10) * 
              (((v_x1 * ((signed long int)dig_H3)) &gt;&gt; 11) + ((signed long int) 32768))) &gt;&gt; 10) + (( signed long int)2097152)) * 
              ((signed long int) dig_H2) + 8192) &gt;&gt; 14));
   v_x1 = (v_x1 - (((((v_x1 &gt;&gt; 15) * (v_x1 &gt;&gt; 15)) &gt;&gt; 7) * ((signed long int)dig_H1)) &gt;&gt; 4));
   v_x1 = (v_x1 &lt; 0 ? 0 : v_x1);
   v_x1 = (v_x1 &gt; 419430400 ? 419430400 : v_x1);
   return (unsigned long int)(v_x1 &gt;&gt; 12);   
}


Actually, BMP280 doesn't monitor relative humidity so you can delete the part related to the humidity control.

#include &lt;Wire.h&gt;

#define BME280_ADDRESS 0x76
unsigned long int temp_raw,pres_raw;
signed long int t_fine;

uint16_t dig_T1;
 int16_t dig_T2;
 int16_t dig_T3;
uint16_t dig_P1;
 int16_t dig_P2;
 int16_t dig_P3;
 int16_t dig_P4;
 int16_t dig_P5;
 int16_t dig_P6;
 int16_t dig_P7;
 int16_t dig_P8;
 int16_t dig_P9;


void setup()
{
    uint8_t osrs_t = 1;             //Temperature oversampling x 1
    uint8_t osrs_p = 1;             //Pressure oversampling x 1
    uint8_t mode = 3;               //Normal mode
    uint8_t t_sb = 5;               //Tstandby 1000ms
    uint8_t filter = 0;             //Filter off 
    uint8_t spi3w_en = 0;           //3-wire SPI Disable

    uint8_t ctrl_meas_reg = (osrs_t &lt;&lt; 5) | (osrs_p &lt;&lt; 2) | mode;
    uint8_t config_reg    = (t_sb &lt;&lt; 5) | (filter &lt;&lt; 2) | spi3w_en;

    Serial.begin(9600);
    Wire.begin();

    writeReg(0xF4,ctrl_meas_reg);
    writeReg(0xF5,config_reg);
    readTrim();                    //
}


void loop()
{
    double temp_act = 0.0, press_act = 0.0;
    signed long int temp_cal;
    unsigned long int press_cal;

    readData();

    temp_cal = calibration_T(temp_raw);
    press_cal = calibration_P(pres_raw);
    temp_act = (double)temp_cal / 100.0;
    press_act = (double)press_cal / 100.0;
    Serial.print("TEMP : ");
    Serial.print(temp_act);
    Serial.print(" DegC  PRESS : ");
    Serial.println(press_act);
    delay(1000);
}
void readTrim()
{
    uint8_t data[32],i=0;                      // Fix 2014/04/06
    Wire.beginTransmission(BME280_ADDRESS);
    Wire.write(0x88);
    Wire.endTransmission();
    Wire.requestFrom(BME280_ADDRESS,24);       // Fix 2014/04/06
    while(Wire.available()){
        data[i] = Wire.read();
        i++;
    }

    Wire.beginTransmission(BME280_ADDRESS);    // Add 2014/04/06
    Wire.write(0xA1);                          // Add 2014/04/06
    Wire.endTransmission();                    // Add 2014/04/06
    Wire.requestFrom(BME280_ADDRESS,1);        // Add 2014/04/06
    data[i] = Wire.read();                     // Add 2014/04/06
    i++;                                       // Add 2014/04/06

    Wire.beginTransmission(BME280_ADDRESS);
    Wire.write(0xE1);
    Wire.endTransmission();
    Wire.requestFrom(BME280_ADDRESS,7);        // Fix 2014/04/06
    while(Wire.available()){
        data[i] = Wire.read();
        i++;    
    }
    dig_T1 = (data[1] &lt;&lt; 8) | data[0];
    dig_T2 = (data[3] &lt;&lt; 8) | data[2];
    dig_T3 = (data[5] &lt;&lt; 8) | data[4];
    dig_P1 = (data[7] &lt;&lt; 8) | data[6];
    dig_P2 = (data[9] &lt;&lt; 8) | data[8];
    dig_P3 = (data[11]&lt;&lt; 8) | data[10];
    dig_P4 = (data[13]&lt;&lt; 8) | data[12];
    dig_P5 = (data[15]&lt;&lt; 8) | data[14];
    dig_P6 = (data[17]&lt;&lt; 8) | data[16];
    dig_P7 = (data[19]&lt;&lt; 8) | data[18];
    dig_P8 = (data[21]&lt;&lt; 8) | data[20];
    dig_P9 = (data[23]&lt;&lt; 8) | data[22];

}
void writeReg(uint8_t reg_address, uint8_t data)
{
    Wire.beginTransmission(BME280_ADDRESS);
    Wire.write(reg_address);
    Wire.write(data);
    Wire.endTransmission();    
}


void readData()
{
    int i = 0;
    uint32_t data[8];
    Wire.beginTransmission(BME280_ADDRESS);
    Wire.write(0xF7);
    Wire.endTransmission();
    Wire.requestFrom(BME280_ADDRESS,8);
    while(Wire.available()){
        data[i] = Wire.read();
        i++;
    }
    pres_raw = (data[0] &lt;&lt; 12) | (data[1] &lt;&lt; 4) | (data[2] &gt;&gt; 4);
    temp_raw = (data[3] &lt;&lt; 12) | (data[4] &lt;&lt; 4) | (data[5] &gt;&gt; 4);
}


signed long int calibration_T(signed long int adc_T)
{

    signed long int var1, var2, T;
    var1 = ((((adc_T &gt;&gt; 3) - ((signed long int)dig_T1&lt;&lt;1))) * ((signed long int)dig_T2)) &gt;&gt; 11;
    var2 = (((((adc_T &gt;&gt; 4) - ((signed long int)dig_T1)) * ((adc_T&gt;&gt;4) - ((signed long int)dig_T1))) &gt;&gt; 12) * ((signed long int)dig_T3)) &gt;&gt; 14;

    t_fine = var1 + var2;
    T = (t_fine * 5 + 128) &gt;&gt; 8;
    return T; 
}

unsigned long int calibration_P(signed long int adc_P)
{
    signed long int var1, var2;
    unsigned long int P;
    var1 = (((signed long int)t_fine)&gt;&gt;1) - (signed long int)64000;
    var2 = (((var1&gt;&gt;2) * (var1&gt;&gt;2)) &gt;&gt; 11) * ((signed long int)dig_P6);
    var2 = var2 + ((var1*((signed long int)dig_P5))&lt;&lt;1);
    var2 = (var2&gt;&gt;2)+(((signed long int)dig_P4)&lt;&lt;16);
    var1 = (((dig_P3 * (((var1&gt;&gt;2)*(var1&gt;&gt;2)) &gt;&gt; 13)) &gt;&gt;3) + ((((signed long int)dig_P2) * var1)&gt;&gt;1))&gt;&gt;18;
    var1 = ((((32768+var1))*((signed long int)dig_P1))&gt;&gt;15);
    if (var1 == 0)
    {
        return 0;
    }    
    P = (((unsigned long int)(((signed long int)1048576)-adc_P)-(var2&gt;&gt;12)))*3125;
    if(P&lt;0x80000000)
    {
       P = (P &lt;&lt; 1) / ((unsigned long int) var1);   
    }
    else
    {
        P = (P / (unsigned long int)var1) * 2;    
    }
    var1 = (((signed long int)dig_P9) * ((signed long int)(((P&gt;&gt;3) * (P&gt;&gt;3))&gt;&gt;13)))&gt;&gt;12;
    var2 = (((signed long int)(P&gt;&gt;2)) * ((signed long int)dig_P8))&gt;&gt;13;
    P = (unsigned long int)((signed long int)P + ((var1 + var2 + dig_P7) &gt;&gt; 4));
    return P;
}