I2C debug program for use with RealTerm. Sends I2C commands to P9 and P10. Run program on mbed. Start RealTerm, select the mbed virtual com port under the port tab, then open RealTerm's I2C command tab. Reset mbed. See http://mbed.org/users/4180_1/notebook/i2c-debug-for-realterm/ for instructions
main.cpp
- Committer:
- 4180_1
- Date:
- 2011-03-14
- Revision:
- 2:fa8c916b42a9
- Parent:
- 1:be1498ba7fb4
File content as of revision 2:fa8c916b42a9:
#include "mbed.h" // The program sends and receives I2C commands using RealTerm's I2C tab feature // Run Realterm on PC and this program on mbed // In RealTerm connect to the mbed's USB virtual COM port // Switch to I2C tab // Type in I2C address & data to read and write and see the response // It is handy to debug complex I2C hardware setups // Prints "No Ack!" when no I2C device responds to the address // // See Instructions at http://mbed.org/users/4180_1/notebook/i2c-debug-for-realterm/ // DigitalOut myled(LED1); Serial pc(USBTX, USBRX); I2C i2c(p9,p10); int main() { char last_command=0; char previous_command=0; char current_char=0; char address=0; char data [255]; char current_byte=0; char cmd[255]; int cmd_count=0; int data_count=0; int read=0; int write=0; int first_data_byte=0; int i=0; myled=1; i2c.frequency(75000); i2c.start(); i2c.stop(); // Send a start message to RealTerm pc.printf("\fmbed I2C debug tool ready\n\r"); // Scan for I2C devices that reply with ack for (i=0; i<=254; i=i+2) { if (i2c.read(i, &data[0], 1) ==0) printf("I2C device detected at address=%2.2X\n\r", i); } data[0]=0; i2c.start(); i2c.stop(); // Loop processing command strings from RealTerm while (1) { current_char = pc.getc(); // Is it a two character ASCII string data byte value if ((current_char <='F') && (current_char !='?')) { // convert to a binary byte if (current_char <='9') current_byte = current_char - '0'; else current_byte =current_char +10 -'A'; current_char = pc.getc(); if (current_char >'F') pc.printf("error|\n\r"); if (current_char <='9') current_byte = (current_byte <<4) | (current_char - '0'); else current_byte = (current_byte <<4)|(current_char +10 -'A'); // first byte after S command is the I2C address if (first_data_byte==1) { first_data_byte=0; address=current_byte; pc.printf(" -I2C address=%2.2X ", address); //Odd I2C address is a read and even is a write if ((address & 0x01) == 0) write=1; else read=1; } else // Read in cmd bytes for write if ((last_command == 'S')&&(read==0)) { cmd[cmd_count]=current_byte; cmd_count++; } // number of bytes for a read if ((last_command =='R')||(read==1)) data_count=current_byte; } else { // Not a number - it is a command character last_command = current_char; switch (last_command) { // Start case 'S': if (previous_command == 'S') i2c.start(); first_data_byte=1; break; // Stop case 'P': // Do the I2C write if (write==1) { pc.printf(" write "); if (i2c.write(address,cmd,cmd_count)!=0) pc.printf(" No Ack! "); for (i=0; i<cmd_count; i++) pc.printf(" cmd=%2.2X ", cmd[i]); } // Do the I2C read if (read==1) { pc.printf(" read "); if (i2c.read(address, data, data_count) != 0) pc.printf(" No Ack! "); for (i=0; i<data_count; i++) pc.printf(" data=%2.2X ",data[i]); } // reset values for next I2C operation i2c.stop(); pc.printf("\n\r"); read=0; data_count=0; cmd_count=0; write=0; first_data_byte=0; break; // Read after write case 'R': read=1; break; // Status request case '?': pc.printf(" mbed ready \n\r"); break; // Unknown or unimplemented command default: pc.printf(" unknown command \n\r"); break; } previous_command = last_command; } } }