Arduino + wt32 / Debugging via Serial

simon654 · September 4, 2009, 10:11pm

Hi there,

I’m trying to get an Arduino Duemilanove to communicate with a bluetooth module (wt32) via its serial connection (Arduino pins 0 and 1, wt32 pins tx0 and rx1).

This is working ok to a point – I can set it up sufficiently to allow my cellphone or laptop to sinc with it. However, to move my project forward I need to monitor the communications between Arduino and the wt32, in order to debug.

I tried to simply echo back everything that I received from the wt32 (i.e. Serial.print() ) and monitor in a terminal program. The wt32 gets ‘angry’ at this, and reports syntax errors (which my code then echoes back on the serial, to produce more syntax errors, etc…)

I was wondering if there is a command in iWrap that means something like “ignore the following text”, so that I could avoid the syntax error infinite loop while still permitting me to debug my code?

To complicate matters, I use a Macbook pro… no windows.

Any help would be appreciated.

lehmanna · September 5, 2009, 5:48am

The “SYNTAX ERROR” occurs as long as you’re in command mode and send garbish instead of commands. But I assume you know that already.

AFAICT, the WT32 breakout supports several GPIO pins that can be set up so as to provide connection information. This way, you can connect one of these pins to one of the Arduino’s pins in order to determine whether there is an active connection or not. Then you can send anything you wish as long as there really is an active connection while at the same time avoid sending rubbish in command mode. IMHO it is way easier to use these GPIO pins than analysing the input from the WT32.

On the other hand, you might as well use the WT32’ multiplexing mode. IIRC it can be clearly determined from the packages whether they were send in command or in data mode, yet you’ll probably use your ability to use the Arduino’s Serial.println() stuff.

simon654 · September 5, 2009, 3:45pm

Thanks for the reply, Alexander.

I’ll try the multiplexing mode. There’s a good description of it in the iWrap guide.

The GPIO solution is probably not what I’m looking for. I’m trying to monitor what the wt32 sends to the Arduino so that my code can move between different states. I’m working with the HFP, linking to a cellphone, and sending/receiving calls.

I’ll post back to this forum when I get it working.

lehmanna · September 5, 2009, 8:06pm

BTW, I think I forgot to mention that you can also simply turn off the command mode “echoing”. There’s a command for that, something like “SET BT ECHO”, but I don’t remember exactly.

simon654 · September 10, 2009, 12:41am

In case anyone is having difficulty using the Hands Free Profile (HFP) with the wt32, here’s a function that I wrote for Ardiuno. It works well – syncs to my cellphone, places calls and receives calls. I have some more refinements to do (e.g. debouncing the input from a keypad attached to the Ardino), but I thought I might as well post the code now.

It is organized as a state machine, which works well with Real-Time Programming. I use a blinkM indicate to the user what state its in (e.g. green = time to sync bluetooth with phone). It is called from within the loop() function.

void loop_bluetooth()

{

char serialOutput[100] = {0};

boolean serialReceived = false;

char serialInputReceived[100] = {0};

// Get input from the wt32 Bluetooth module

if (Serial.available() > 0)

{

serialInput[serialNextIndex] = Serial.read();

if (serialInput[serialNextIndex] == ‘\n’)

{

strcpy(serialInputReceived, serialInput);

serialNextIndex = 0;

}

else

{

serialNextIndex++;

}

// Next State Logic

//

// SETUP

// |

// |/

// V

// READY

// |

// |/

// V

// CONNECTED <-------------+

// | | |

// |/ |/ |

// V V |

// CALL RECEIVED DIALING |

// | | |

// |/ |/ |

// V V |

// ANSWER CALL DIAL NUMBER |

// | | |

// |/ |/ |

// V V |

// CALL IN PROGRESS |

// | |

// |/ |

// V |

// HANGING UP -------------+

//

switch(btState)

{

case STATE_SETUP:

if(setupComplete) btState = STATE_READY_TO_CONNECT;

break;

case STATE_READY_TO_CONNECT:

if (stringCompare(serialInputReceived, “HFP 0 READY”)) btState = STATE_CONNECTED;

break;

case STATE_CONNECTED:

if (stringCompare(serialInputReceived, “HFP 0 RING”)) btState = STATE_CALL_RECEIVED;

if (digitalRead(HOOK) == HIGH) btState = STATE_DIALING;