Derek Calland

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7 years, 1 month ago.  This question has been closed. Reason: Off Topic

I2C Pins??

I'm successfully reading the temperature from the TMP102 device but only if I use pin references 28 and 29 in the program below although my device is actually connected via pins 9 and 10? Is there a simple explanation? If I change the program to pins 9 and 10 I get no readings?

 
#include "mbed.h"
#include "TextLCD.h"
#include "TMP102.h"

I2C i2c(p28, p27); // sda, scl
TextLCD lcd(p15, p16, p17, p18, p19, p20); // rs, e, d4-d7

TMP102 TMP102(p28,p27,0x90); //Define SDA, SCL pin and i2c address

float TempReading() {
    float value;
    value = TMP102.read();
    return value;
    }  

int main() {
   lcd.printf("I2CU! Searching for I2C devices...\n");

    int count = 0;
    for (int address=0; address<256; address+=2) {
        if (!i2c.write(address, NULL, 0)) { // 0 returned is ok
           lcd.printf(" - I2C device found at address 0x%02X\n", address);
            count++;
            wait(5);
            lcd.cls();
        }
    }
    lcd.printf("%d devices found\n", count); 
    while (1){
        float temperature = TempReading();
        lcd.printf("Temperature: %2.f degC\n", temperature);
        }
}