Joseph Ellsworth / Mbed 2 deprecated I2C_address_scanner

I2C address scanner - Scans I2C bus on specified pins and prints all addresses where a active responder is found.

Dependencies:   mbed

Find address for I2C device

Scans all addreses on a I2C bus and reports those it is able to sucessfully communicate with.

One problem with I2C is that sometimes we receive chips without proper documentation and can not determine what address we should use ot communicate with that chip. This library seeks to identify the chips by attempting to communicate with each address and if it suceeds it assumes there is a chip present.

I have tested this with a clock chip, temperature sensor, OLED device and FRAM chip. It worked for all of them but there is a chance that some chips will not respond without a specific API call so there may be some chips it could not locate.

main.cpp

Committer:
joeata2wh
Date:
2016-03-30
Revision:
8:ead6147e31a4
Parent:
7:5962e77516ac

File content as of revision 8:ead6147e31a4:

/* Scan I2C bus on specified pins and prints out
* the all address where an active device responds.
*
  By Joseph Ellsworth CTO of A2WH
  Take a look at A2WH.com Producing Water from Air using Solar Energy
  March-2016 License: https://developer.mbed.org/handbook/MIT-Licence 
  Please contact us http://a2wh.com for help with custom design projects.

  
* Don't forget 3K pull-up resistors on sda,scl 
* 
* I tested this by soldering in a I2C chip known to respond at
* address dec=120 hex=70 and the utility got the ack as expected.
* when the chip was de-soldered it was no longer detected.  
*/

#include "mbed.h"

Serial pc(USBTX, USBRX);
Serial pc2(USBTX, USBRX);

 #define D_SDA                  PB_7 
 #define D_SCL                  PB_6 
   // sda=PB7, scl=PB_6 Pins specific to Nucleo-F303K8
  // must change pins to match your board.

I2C i2c(D_SDA, D_SCL);  
  
DigitalOut myled(LED1);
 
int ack;   
int address;  
void scanI2C() {
  for(address=1;address<127;address++) {    
    ack = i2c.write(address, "11", 1);
    if (ack == 0) {
       pc.printf("\tFound at %3d -- %3x\r\n", address,address);
    }    
    wait(0.05);
  } 
}
 
int main() {
  pc.baud(9600);
  pc.printf("I2C scanner \r\n");
  scanI2C();
  pc.printf("Finished Scan\r\n");
  // just blink to let us know the CPU is alive 
  while(1) { 
      wait(5.0);          
      myled = !myled;
  }
}