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:
- 2011-03-08
- Revision:
- 0:0c54b73b002c
- Child:
- 1:be1498ba7fb4
File content as of revision 0:0c54b73b002c:
#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 "noack!" when no I2C device responds DigitalOut myled(LED1); Serial pc(USBTX, USBRX); I2C i2c(p9,p10); char data_length=0; int read=0; int write=0; //ugly code structure - should start over and fix this later //now that I understand syntax for command strings a bit more - but it works // Read in two ASCII characters and convert to a byte // ...unless a command character is found int getbyte(char *data) { char charin=0; charin = pc.getc(); if (charin == 'R') { read=1; if (getbyte(&data_length)==0) pc.printf("error"); return 2; } if (charin == 'P') return 3; if (charin > 'F') return 0; if (charin <='9') charin = charin - '0'; else charin = charin +10 - 'A'; *data = charin << 4; charin = pc.getc(); if (charin > 'F') return 0; if (charin <='9') charin = charin - '0'; else charin = charin +10 - 'A'; *data = *data | charin; return 1; } int main() { char command=0; char address=0x40; char data[255]; char cmd[255]; int cmd_count=0; int more_cmd = 0; int i=0; myled=1; data[0]=0; data[1]=0; i2c.frequency(75000); i2c.start(); i2c.start(); pc.printf("\fmbed I2C ready\n\r"); // loop forever waiting for PC serial commands while (1) { command = pc.getc(); switch (command) { case 'S': //Start - automatic start sent on read or write data_length=0; cmd_count=0; read=0; write=0; // in case of multiple starts while (getbyte(&address)==0) {i2c.start();}; pc.printf(" - I2C address=%2.2X ", address); //odd address means a read, otherwise a write if ((address & 0x01) == 1) read=1; else write=1; if (read ==1) { //read number of bytes to read if (getbyte(&data_length)==0) break; } if (write==1) { more_cmd =1; while (more_cmd==1) { if (getbyte(&cmd[cmd_count])>=2) { pc.printf(" write "); // write I2C command(s) if (i2c.write(address, cmd, cmd_count)!=0) pc.printf(" noack! "); for (i=0; i<cmd_count; i++) pc.printf(" command=%2.2X ", cmd[i]); cmd_count=0; more_cmd=0; write = 0; } else cmd_count++; } if (read==0) pc.printf("\n\r");; } break; case 'P': //Stop if (read == 1) { pc.printf(" read "); // read I2C data if (i2c.read(address, data, data_length)!=0) pc.printf(" noack! "); read = 0; write = 0; // send I2C data back to PC serial port for (i=0; i<data_length; i++) pc.printf(" data=%2.2X ",data[i]); } pc.printf("\n\r"); data_length=0; cmd_count=0; i2c.stop(); break; case 'R': //automatic read after write - read number of bytes to read if (getbyte(&data_length)==0) break; break; case '?': //Status pc.printf(" mbed ready \n\r"); break; default: myled = 0; break; } } }