Antoniolinux B.

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8 years, 4 months ago.

Infrared Thermometer MLX90614 and Nucleo STM32L152R3

Hi to all, i write this:

Serial pc(PA_9,PA_10); //Serial 1  TX,  RX  PER DEBUG. 
I2C i2c(PB_9,PB_8);
 
const int addr = 0x5A;
  char data_read[2];
int main() {
    pc.printf("\nI2C Scanner");
   
	 data_read[1]='A';
	 data_read[0]='B';
    while(1) {
        int error, address;
        int nDevices;
      
        pc.printf("Scanning...\n");
        
         nDevices = 0;
         
          for(address = 1; address < 127; address++ ) 
          {
						
            i2c.start();
            error = i2c.write(address << 1); //We shift it left because mbed takes in 8 bit addreses
            i2c.stop();
            if (error == 1)
            {
              pc.printf("I2C device found at address 0x%X", address); //Returns 7-bit addres
		 int status = i2c.read((address << 1),data_read, 2);			
		pc.printf("%d-", status);
			pc.printf("%d-", (int)data_read[1]);
			pc.printf("%d\n", (int)data_read[0]);
              nDevices++;
            }
 
          }
          if (nDevices == 0){
            pc.printf("No I2C devices found\n");
					}
          else{
            pc.printf("\ndone\n"); 
					  
					}
        
          wait(5);           // wait 5 seconds for next scan
          
            }
        }

in this code i can read the address of IR Thermometer, the address is 0XA5, but i can't read the value of temperature, in fact if i print the status i read 0, the data_read[0] and data_read[1] have the value 255 , i don't know where is the problem can you help me?

best regards. A.

1 Answer

David Thedens
8 years, 4 months ago.

why not leverage from github https://github.com/sparkfun/SparkFun_MLX90614_Arduino_Library

Hi David thanks for your answer, i read the code that you post and write this:

int status=i2c.read(0x08); // equal for  int status=i2c.read(0x07);
p1=i2c.read(1);     //Tobj low byte
p2=i2c.read(1);     //Tobj heigh byte
p3=i2c.read(0);     //PEC
pc.printf("%d-", status);
pc.printf("data-");
pc.printf("%d-", (int)p1);
pc.printf("%d-", (int)p2);
pc.printf("%d-", (int)p3);

i see that i read that status is 1, i think is good because i can read the Tobj he problem is that p1,p2 and p3 is 255 i don't understand where is the error do you have some idea?

posted by Antoniolinux B. 03 Dec 2015