Hi.
I have a BMP 180 barometer and a MPU 6050 gyroscope. I connected them with arduino mega 2560 as attached in the picture.
if its not clear:
Barometer with arduino
GND = GND
VCC = 3.3v
SDA = SDA (pin 20)
SCL = SCL (PIN 21)
gyroscope with arduino
GND = GND
VCC = 3.3v
SDA = SDA (pin 20)
SCL = SCL (PIN 21)
INT = PIN 2.
I was successful with coding both separately. I used following code for barometer
```
/*********************************************************
Bosch Pressure Sensor BMP085 / BMP180 readout routine
for the Arduino platform.
Compiled by Leo Nutz
www.ALTDuino.de
**********************************************************/
#include <Wire.h>
#define ADDRESS_SENSOR 0x77 // Sensor address
int16_t ac1, ac2, ac3, b1, b2, mb, mc, md; // Store sensor PROM values from BMP180
uint16_t ac4, ac5, ac6; // Store sensor PROM values from BMP180
// Ultra Low Power OSS = 0, OSD = 5ms
// Standard OSS = 1, OSD = 8ms
// High OSS = 2, OSD = 14ms
// Ultra High Resolution OSS = 3, OSD = 26ms
const uint8_t oss = 3; // Set oversampling setting
const uint8_t osd = 26; // with corresponding oversampling delay
float T, P; // Set global variables for temperature and pressure
void setup()
{
Wire.begin(); // Activate I2C
Serial.begin(9600); // Set up serial port
init_SENSOR(); // Initialize baro sensor variables
delay(100);
}
void loop()
{
int32_t b5;
b5 = temperature(); // Read and calculate temperature (T)
Serial.print("Temperature: ");
Serial.print(T, 2);
Serial.print(" C, ");
Serial.print(1.8 * T + 32.0, 2);
Serial.println(" F");
P = pressure(b5); // Read and calculate pressure (P)
Serial.print("Pressure: ");
Serial.print(P, 2);
Serial.print(" mbar, ");
Serial.print(P * 0.0295299830714, 2);
Serial.println(" inHg");
Serial.println("");
delay(500); // Delay between each readout
}
/**********************************************
Initialize sensor variables
**********************************************/
void init_SENSOR()
{
ac1 = read_2_bytes(0xAA);
ac2 = read_2_bytes(0xAC);
ac3 = read_2_bytes(0xAE);
ac4 = read_2_bytes(0xB0);
ac5 = read_2_bytes(0xB2);
ac6 = read_2_bytes(0xB4);
b1 = read_2_bytes(0xB6);
b2 = read_2_bytes(0xB8);
mb = read_2_bytes(0xBA);
mc = read_2_bytes(0xBC);
md = read_2_bytes(0xBE);
Serial.println("");
Serial.println("Sensor calibration data:");
Serial.print(F("AC1 = ")); Serial.println(ac1);
Serial.print(F("AC2 = ")); Serial.println(ac2);
Serial.print(F("AC3 = ")); Serial.println(ac3);
Serial.print(F("AC4 = ")); Serial.println(ac4);
Serial.print(F("AC5 = ")); Serial.println(ac5);
Serial.print(F("AC6 = ")); Serial.println(ac6);
Serial.print(F("B1 = ")); Serial.println(b1);
Serial.print(F("B2 = ")); Serial.println(b2);
Serial.print(F("MB = ")); Serial.println(mb);
Serial.print(F("MC = ")); Serial.println(mc);
Serial.print(F("MD = ")); Serial.println(md);
Serial.println("");
}
/**********************************************
Calcualte pressure readings
**********************************************/
float pressure(int32_t b5)
{
int32_t x1, x2, x3, b3, b6, p, UP;
uint32_t b4, b7;
UP = read_pressure(); // Read raw pressure
b6 = b5 - 4000;
x1 = (b2 * (b6 * b6 >> 12)) >> 11;
x2 = ac2 * b6 >> 11;
x3 = x1 + x2;
b3 = (((ac1 * 4 + x3) << oss) + 2) >> 2;
x1 = ac3 * b6 >> 13;
x2 = (b1 * (b6 * b6 >> 12)) >> 16;
x3 = ((x1 + x2) + 2) >> 2;
b4 = (ac4 * (uint32_t)(x3 + 32768)) >> 15;
b7 = ((uint32_t)UP - b3) * (50000 >> oss);
if(b7 < 0x80000000) { p = (b7 << 1) / b4; } else { p = (b7 / b4) << 1; } // or p = b7 < 0x80000000 ? (b7 * 2) / b4 : (b7 / b4) * 2;
x1 = (p >> 8) * (p >> 8);
x1 = (x1 * 3038) >> 16;
x2 = (-7357 * p) >> 16;
return (p + ((x1 + x2 + 3791) >> 4)) / 100.0f; // Return pressure in mbar
}
/**********************************************
Read uncompensated temperature
**********************************************/
int32_t temperature()
{
int32_t x1, x2, b5, UT;
Wire.beginTransmission(ADDRESS_SENSOR); // Start transmission to device
Wire.write(0xf4); // Sends register address
Wire.write(0x2e); // Write data
Wire.endTransmission(); // End transmission
delay(5); // Datasheet suggests 4.5 ms
UT = read_2_bytes(0xf6); // Read uncompensated TEMPERATURE value
// Calculate true temperature
x1 = (UT - (int32_t)ac6) * (int32_t)ac5 >> 15;
x2 = ((int32_t)mc << 11) / (x1 + (int32_t)md);
b5 = x1 + x2;
T = (b5 + 8) >> 4;
T = T / 10.0; // Temperature in celsius
return b5;
}
/**********************************************
Read uncompensated pressure value
**********************************************/
int32_t read_pressure()
{
int32_t value;
Wire.beginTransmission(ADDRESS_SENSOR); // Start transmission to device
Wire.write(0xf4); // Sends register address to read from
Wire.write(0x34 + (oss << 6)); // Write data
Wire.endTransmission(); // SEd transmission
delay(osd); // Oversampling setting delay
Wire.beginTransmission(ADDRESS_SENSOR);
Wire.write(0xf6); // Register to read
Wire.endTransmission();
Wire.requestFrom(ADDRESS_SENSOR, 3); // Request three bytes
if(Wire.available() >= 3)
{
value = (((int32_t)Wire.read() << 16) | ((int32_t)Wire.read() << 8) | ((int32_t)Wire.read())) >> (8 - oss);
}
return value; // Return value
}
/**********************************************
Read 1 byte from the BMP sensor
**********************************************/
uint8_t read_1_byte(uint8_t code)
{
uint8_t value;
Wire.beginTransmission(ADDRESS_SENSOR); // Start transmission to device
Wire.write(code); // Sends register address to read from
Wire.endTransmission(); // End transmission
Wire.requestFrom(ADDRESS_SENSOR, 1); // Request data for 1 byte to be read
if(Wire.available() >= 1)
{
value = Wire.read(); // Get 1 byte of data
}
return value; // Return value
}
/**********************************************
Read 2 bytes from the BMP sensor
*********************************************/
uint16_t read_2_bytes(uint8_t code)
{
uint16_t value;
Wire.beginTransmission(ADDRESS_SENSOR); // Start transmission to device
Wire.write(code); // Sends register address to read from
Wire.endTransmission(); // End transmission
Wire.requestFrom(ADDRESS_SENSOR, 2); // Request 2 bytes from device
if(Wire.available() >= 2)
{
value = (Wire.read() << 8) | Wire.read(); // Get 2 bytes of data
}
return value; // Return value
}
```
I will attach a file with the code i used for the gyroscope.
But what i need to do is code the arduino to get the output values of these two i2c devices at the same time.
Is it possible to use two I2C devices connect to a single arduino and work with both togather?
If Yes Please let me understand how to call them when i need the outputs of them.
Please Help me.
Thank you. 
1---07-12-13(pure).txt (15.9 KB)
