Can not get Notify messages from xTaskNotifyTake()

[sakunamary]

Hi guys:
I am trying to make a canbus thermocouple module with HeliOS ; the working flow as follow:
step1: power up and run init scripts for init
step2: create two task 1)get temperature 2)write canbus data and send out
wait for 750ms and make sure MAX6675 get the correct temperature data ,IN the meanwhile canbus data will NOT send out
step3: Task1:get temperature will run every 750ms and write the data in a float struct .And then notify task2 to send data out

I tested example-- WaitNotify.ino ,it work well . so I write my pgm base on WaitNotify.ino,here is source files

sourcefile.zip

The main issue is xTaskNotifyTake(task_) can not attached ,not working

Task1 send out notifications :

void taskThermo_Get(xTask task_, xTaskParm parm_)
{
/* Get the task handle for the task that will receive the
direct-to-task notification. */
xTask WriteCANBUSTask = xTaskGetHandleByName("WRITECANBUS");

    temperature_data.BT_AvgTemp=30.12;
    temperature_data.ET_CurTemp=28.66; 

    Serial.print("task thermo_get");
    Serial.print("  ") ;
    Serial.print(temperature_data.BT_AvgTemp);
    Serial.print("  ") ;
    Serial.print(temperature_data.ET_CurTemp);
    Serial.println(" ");


    if (WriteCANBUSTask){  
        //Serial.println("geted task_writecanbus handler"); 
        /* Send the direct-to-task notification of "HELLO"
        which is five bytes. */
        Serial.println("task WriteCANBUSTask send noti "); --------> it's work 
        xTaskNotifyGive(WriteCANBUSTask,2, "OK");
    }
}

task2 :Receiver notifications
void taskCanbus_Write(xTask task_, xTaskParm parm_)
{
String notif_str = "";
Serial.print("before notif_str");
Serial.println(notif_str);
xTaskNotification notif = xTaskNotifyTake(task_); ------>here ,not working .
notif_str = notif->notificationValue;------>here ,not working .
Serial.print("after notif_str");
Serial.println(notif_str);------->print out nothing...which is suppose is 'OK'

if ( notif ){. -------> here is not working neither
notif_str = notif->notificationValue;-------> here is not working neither
Serial.println(notif_str);-------> here is not working neither
xMemFree(notif);-------> here is not working neither
}

The rest of codes is the same as example ino file but the task name....
create task as below:
xTask GetThermoTask = xTaskCreate("GET_THERMO", taskThermo_Get,NULL);
xTask WriteCANBUSTask = xTaskCreate("WRITECANBUS", taskCanbus_Write, NULL);

and then set task in waiting mode :
xTaskWait(GetThermoTask);
xTaskWait(WriteCANBUSTask);
and set sending notify task in running mode which loop in 1s.
xTaskChangePeriod(GetThermoTask, 1000); //1000ms

Thank you for you guys answering!!!
Best wishes!!!

[MannyPeterson]

@sakunamary

Let's start with the following code for taskCanbus_Write().

void taskCanbus_Write(xTask task_, xTaskParm parm_) {
  int bytes = 0;
  xTaskNotification notif = xTaskNotifyTake(task_);
  bytes = notif->notificationBytes;
  Serial.println("Notification Bytes: " + bytes);
  xMemFree(notif);
}

The output should be as follows.

Notification Bytes: 2

Please let me know if your output matches mine.

Thank You,

Manny

[sakunamary]

Hi

@sakunamary

Let's start with the following code for taskCanbus_Write().

void taskCanbus_Write(xTask task_, xTaskParm parm_) {
  int bytes = 0;
  xTaskNotification notif = xTaskNotifyTake(task_);
  bytes = notif->notificationBytes;
  Serial.println("Notification Bytes: " + bytes);
  xMemFree(notif);
}

The output should be as follows.

Notification Bytes: 2

Please let me know if your output matches mine.

Thank You,

Manny

Hi Manny
My output match your result
Notification Bytes: 2
seem xTaskNotifyGive send out a message

[sakunamary]

Finally !!! It work now !!!

void taskCanbus_Write(xTask task_, xTaskParm parm_)
{
char * notif_str ;----> change type from string to char* is working !
xTaskNotification notif = xTaskNotifyTake(task_);
xMemFree(notif);
}

[MannyPeterson]

@sakunamary

Nice job! I was just going to tell you to use a char array and not an Arduino String. But you got to the answer first.

I am closing the issue for now. If you have any other issues feel free to open a new issue.

Best wishes!