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@1:2363995f603f, 2016-03-20 (annotated)

Committer:
joeata2wh
Date:
Sun Mar 20 23:48:48 2016 +0000
Revision:
1:2363995f603f
Parent:
0:befb557584fb
Child:
2:e90c47d4f358
working version

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 0:befb557584fb 2 * the address of all pins where a active responder
joeata2wh 0:befb557584fb 3 * is found.
joeata2wh 0:befb557584fb 4 *
joeata2wh 0:befb557584fb 5 * By Joe Elsworth CTO of A2WH
joeata2wh 0:befb557584fb 6 * Free use for al but no warranty, no promises.
joeata2wh 0:befb557584fb 7 * Don't forget 3K pullup sda,scl */
joeata2wh 0:befb557584fb 8
joeata2wh 0:befb557584fb 9 #include "mbed.h"
joeata2wh 0:befb557584fb 10
joeata2wh 0:befb557584fb 11
joeata2wh 0:befb557584fb 12 Serial pc(USBTX, USBRX);
joeata2wh 0:befb557584fb 13
joeata2wh 1:2363995f603f 14 #define D_SDA PB_7
joeata2wh 0:befb557584fb 15 #define D_SCL PB_6
joeata2wh 0:befb557584fb 16 // sda=PB7, scl=PB_6 Pins specific to Nucleo-F303K8
joeata2wh 0:befb557584fb 17 // must change pins to match your board.
joeata2wh 0:befb557584fb 18
joeata2wh 0:befb557584fb 19 I2C i2c(D_SDA, D_SCL);
joeata2wh 0:befb557584fb 20
joeata2wh 0:befb557584fb 21 DigitalOut myled(LED1);
joeata2wh 0:befb557584fb 22
joeata2wh 0:befb557584fb 23 void scanI2C() {
joeata2wh 0:befb557584fb 24 int address;
joeata2wh 0:befb557584fb 25 int ack;
joeata2wh 0:befb557584fb 26 for(address=1;address<127;address++) {
joeata2wh 0:befb557584fb 27 ack = i2c.write(address, "11", 1);
joeata2wh 0:befb557584fb 28 if (ack == 0) {
joeata2wh 0:befb557584fb 29 pc.printf("\tFound at %3d -- %3x\r\n", address,address);
joeata2wh 0:befb557584fb 30 }
joeata2wh 0:befb557584fb 31 wait(0.05);
joeata2wh 0:befb557584fb 32 }
joeata2wh 0:befb557584fb 33 }
joeata2wh 0:befb557584fb 34
joeata2wh 0:befb557584fb 35 int main() {
joeata2wh 0:befb557584fb 36 pc.baud(9600);
joeata2wh 0:befb557584fb 37 pc.printf("I2C scanner \r\n");
joeata2wh 0:befb557584fb 38 scanI2C();
joeata2wh 0:befb557584fb 39 pc.printf("Finished Scan\r\n");
joeata2wh 0:befb557584fb 40
joeata2wh 0:befb557584fb 41 ack = i2c.write(71, "11", 1);
joeata2wh 0:befb557584fb 42
joeata2wh 0:befb557584fb 43 while(1) {
joeata2wh 0:befb557584fb 44 wait(5.0);
joeata2wh 0:befb557584fb 45 myled = !myled;
joeata2wh 0:befb557584fb 46 }
joeata2wh 0:befb557584fb 47 }
joeata2wh 0:befb557584fb 48