David Wahl
Scans for I2C devices and prints out the addresses to serial. Scans once at startup and again whenever it receives a "s" over the serial port. When using putty, turn "Local Echo" and "Local line editing" options to "Force On". Tested on a Nucleo F446RE but should be portable to most boards with minimal editing.
Revision 0:300d8042b9fe, committed 2019-08-07
- Comitter:
- dmwahl
- Date:
- Wed Aug 07 16:20:58 2019 +0000
- Commit message:
- Initial commit
Changed in this revision
| main.cpp | Show annotated file Show diff for this revision Revisions of this file |
| mbed.bld | Show annotated file Show diff for this revision Revisions of this file |
diff -r 000000000000 -r 300d8042b9fe main.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp Wed Aug 07 16:20:58 2019 +0000
@@ -0,0 +1,73 @@
+// Basic I2C scanner. Runs at startup and when it receives a "s" character via serial. Prints out the address of any devices found on the bus.
+
+#include "mbed.h"
+#include <string>
+
+bool i2cScan = true;
+bool debugEnabled = true;
+
+I2C i2c(PB_9, PB_8); // sda, scl
+//I2C i2c(D4, D5); // sda, scl
+Serial pc(USBTX, USBRX, 115200); // tx, rx, baud
+
+// Begin serial port functions/variables
+Timer serialTimer;
+
+char cSerialRx; // Raw character from serialRx
+string sSerialRx; // Serial received string
+
+void serialRx_interrupt()
+{
+ // If time since last character received is too long, reset the received characters string and unlock the i2c bus
+ if ((uint32_t)serialTimer.read_ms() > 5) {
+ sSerialRx.clear();
+ }
+
+ cSerialRx=pc.getc(); // Get individual characters from serial
+ sSerialRx+=cSerialRx; // and string them together
+
+ switch (cSerialRx) {
+ case 's': // Trigger a I2C scan
+ i2cScan = true;
+
+ sSerialRx.clear(); // clear serial buffer
+ break;
+
+
+ case 'q':
+ if (debugEnabled) {
+ pc.printf("Restarting...\n\r");
+ }
+ NVIC_SystemReset();
+
+ default:
+ // No action by default; wait for next character
+ //break;
+ }
+ serialTimer.reset(); // Reset timer
+}
+// End serial port functions/variables
+
+int main()
+{
+ int error = 0;
+
+ pc.attach(&serialRx_interrupt, Serial::RxIrq); // Create serial rx interrupt to process incoming commands
+ serialTimer.start(); // Serial timer to keep track of time between characters
+
+ i2c.frequency(100000);
+
+ while (true) {
+ if (i2cScan) {
+ i2cScan = false;
+ for(int i = 0; i < 128 ; i++) {
+ i2c.start();
+ error = i2c.write(i << 1);
+ i2c.stop();
+ if (error == 1) {
+ printf("0x%X\r\n", i); //Return 7-bit address
+ }
+ }
+ }
+ }
+}
\ No newline at end of file
diff -r 000000000000 -r 300d8042b9fe mbed.bld --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed.bld Wed Aug 07 16:20:58 2019 +0000 @@ -0,0 +1,1 @@ +https://os.mbed.com/users/mbed_official/code/mbed/builds/65be27845400 \ No newline at end of file