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@8:ead6147e31a4, 2016-03-30 (annotated)

Committer:
joeata2wh
Date:
Wed Mar 30 14:58:05 2016 +0000
Revision:
8:ead6147e31a4
Parent:
7:5962e77516ac 
Update to use standard MIT license

Who changed what in which revision?

UserRevisionLine numberNew contents of line
joeata2wh 0:befb557584fb 1 /* Scan I2C bus on specified pins and prints out
joeata2wh 6:02a058f2ec6f 2 * the all address where an active device responds.
joeata2wh 0:befb557584fb 3 *
joeata2wh 8:ead6147e31a4 4 By Joseph Ellsworth CTO of A2WH
joeata2wh 8:ead6147e31a4 5 Take a look at A2WH.com Producing Water from Air using Solar Energy
joeata2wh 8:ead6147e31a4 6 March-2016 License: https://developer.mbed.org/handbook/MIT-Licence
joeata2wh 8:ead6147e31a4 7 Please contact us http://a2wh.com for help with custom design projects.
joeata2wh 8:ead6147e31a4 8
joeata2wh 8:ead6147e31a4 9
joeata2wh 6:02a058f2ec6f 10 * Don't forget 3K pull-up resistors on sda,scl
joeata2wh 2:e90c47d4f358 11 *
joeata2wh 2:e90c47d4f358 12 * I tested this by soldering in a I2C chip known to respond at
joeata2wh 2:e90c47d4f358 13 * address dec=120 hex=70 and the utility got the ack as expected.
joeata2wh 2:e90c47d4f358 14 * when the chip was de-soldered it was no longer detected.
joeata2wh 2:e90c47d4f358 15 */
joeata2wh 0:befb557584fb 16
joeata2wh 0:befb557584fb 17 #include "mbed.h"
joeata2wh 0:befb557584fb 18
joeata2wh 0:befb557584fb 19 Serial pc(USBTX, USBRX);
joe ellsworth 7:5962e77516ac 20 Serial pc2(USBTX, USBRX);
joeata2wh 0:befb557584fb 21
joeata2wh 1:2363995f603f 22 #define D_SDA PB_7
joeata2wh 0:befb557584fb 23 #define D_SCL PB_6
joeata2wh 0:befb557584fb 24 // sda=PB7, scl=PB_6 Pins specific to Nucleo-F303K8
joeata2wh 0:befb557584fb 25 // must change pins to match your board.
joeata2wh 0:befb557584fb 26
joeata2wh 0:befb557584fb 27 I2C i2c(D_SDA, D_SCL);
joeata2wh 0:befb557584fb 28
joeata2wh 0:befb557584fb 29 DigitalOut myled(LED1);
joeata2wh 0:befb557584fb 30
joeata2wh 4:ad1195c10812 31 int ack;
joeata2wh 6:02a058f2ec6f 32 int address;
joeata2wh 0:befb557584fb 33 void scanI2C() {
joeata2wh 0:befb557584fb 34 for(address=1;address<127;address++) {
joeata2wh 0:befb557584fb 35 ack = i2c.write(address, "11", 1);
joeata2wh 0:befb557584fb 36 if (ack == 0) {
joeata2wh 0:befb557584fb 37 pc.printf("\tFound at %3d -- %3x\r\n", address,address);
joeata2wh 0:befb557584fb 38 }
joeata2wh 0:befb557584fb 39 wait(0.05);
joeata2wh 0:befb557584fb 40 }
joeata2wh 0:befb557584fb 41 }
joeata2wh 0:befb557584fb 42
joeata2wh 0:befb557584fb 43 int main() {
joeata2wh 0:befb557584fb 44 pc.baud(9600);
joeata2wh 0:befb557584fb 45 pc.printf("I2C scanner \r\n");
joeata2wh 0:befb557584fb 46 scanI2C();
joeata2wh 0:befb557584fb 47 pc.printf("Finished Scan\r\n");
joeata2wh 5:a4fddd74263c 48 // just blink to let us know the CPU is alive
joeata2wh 0:befb557584fb 49 while(1) {
joeata2wh 0:befb557584fb 50 wait(5.0);
joeata2wh 0:befb557584fb 51 myled = !myled;
joeata2wh 0:befb557584fb 52 }
joeata2wh 0:befb557584fb 53 }
joeata2wh 0:befb557584fb 54