Yun rev 2 Bridge library conflict

[edouardreg]

Hello,

If you use the bridge library to write to the µSD card, as soon as you include Arduino_FreeRTOS in your sketch, you can't access anymore to the file on the SD card.

Just include your library into datalogger example sketch break it : the sketch is no more able to open and write to the file. The serial link hang.

I use a Yun rev 2, up to date with arduino 1.8.7 (last one).

Thanks

[feilipu]

If you mean that you are adding

#include <Arduino_FreeRTOS.h>

into your datalogger example file, and doing nothing else, then yes. That will break everything.

This is because including the header file immediately converts the run-time to use a scheduler, and the loop() function should then be empty. Things are done in tasks. The loop() function is being run as part of the idle task, with a minimal stack allocation. Using String functions is a good way to "blow up" the minimal stack, and this is probably why the program is failing.

[feilipu]

Your datalogger needs to look like this.

/*
  SD card datalogger

  This example shows how to log data from three analog sensors
  to an SD card using the SD library.

  The circuit:
   analog sensors on analog ins 0, 1, and 2
   SD card attached to SPI bus as follows:
 ** MOSI - pin 11
 ** MISO - pin 12
 ** CLK - pin 13
 ** CS - pin 4 (for MKRZero SD: SDCARD_SS_PIN)

  created  24 Nov 2010
  modified 9 Apr 2012
  by Tom Igoe

  This example code is in the public domain.

*/

#include <Arduino_FreeRTOS.h>

#include <SPI.h>
#include <SD.h>

const int chipSelect = 4;

void *DataloggerTask(void* params) {
  (void) params;

  String dataString;

  // Open serial communications and wait for port to open:
  Serial.begin(9600);
  while (!Serial) {
    ; // wait for serial port to connect. Needed for native USB port only
  }

  Serial.print("Initializing SD card...");

  // see if the card is present and can be initialized:
  if (!SD.begin(chipSelect)) {
    Serial.println("Card failed, or not present");
  } else
    Serial.println("Card initialized.");

  // open the file. note that only one file can be open at a time,
  // so you have to close this one before opening another.
  File dataFile = SD.open("datalog.txt", FILE_WRITE);

  while (true)
  {
    // make a string for assembling the data to log:
    dataString = "";

    // read three sensors and append to the string:
    for (int analogPin = 0; analogPin < 3; analogPin++) {
      int sensor = analogRead(analogPin);
      dataString += String(sensor);
      if (analogPin < 2) {
        dataString += ",";
      }
    }

    // if the file is available, write to it:
    if (dataFile) {
      dataFile.println(dataString);
      dataFile.close();
      // print to the serial port too:
      Serial.println(dataString);
    }
    // if the file isn't open, pop up an error:
    else {
      Serial.println("error opening datalog.txt");
    }
  }
}

void setup() {
    xTaskCreate(DataloggerTask, "datalogger", 512, NULL, 1, NULL);
}

void loop() {
}