Just including Wire.h library make the sheduler stop working.

[JBRO8081]

Code 1
/---------------------------------#includes---------------------------------/
#include <SPI.h>
#include <Wire.h>

#include <Arduino_FreeRTOS.h>
#include <queue.h>>

/--------------------------------#defines-----------------------------------/

#define PIN_TEMP_SENSOR A0
#define PIN_TEST_ANA A3
#define PIN_RELAY_GND 5
#define PIN_RELAY_EXT 6
#define PIN_SPI_CS_DAC 9
#define PIN_SPI_CS_ADC 10
#define ADC_VREF 2500 // 2500mV
#define ADDR_DIGITAL_POT 0x29
#define I2C_CLK_RATE 400000
#define SERIAL_BAUD_RATE 9600

/*

• Serial Protocol
• ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
• |Sensor Name|Channel No|Val LSB|Val MSB|\n|
• '''''''''''''''''''''''''''''''''''''''''''
• @sensor Name : T for temp, V for ADC_V ,C for ADC_C,P for Pot val,

•            D for DAC Val.
  

• @channel No : Channel number of sensor if applicable or default it to zero.
• @Val LSB : Lower byte of raw value from sensor.
• @Val MSB : Upper byte of raw value from sensor.
• @\n : Termination byte to be new line.
• Please Note that Raw value proessing is expected to taken care by host due
• to Limited processing capability of atmega 328P. Total byte size is limited
• to 5 byte for performance reasons.
  */
  #define QUEUE_SERIAL_SEND_DEPTH 10
  #define QUEUE_SERIAL_SEND_BYTE_MAX_SIZE 5

#define TASK_SERIAL_SEND_STACK 128
#define TASK_SERIAL_SEND_PRIORITY 2

#define TASK_SERIAL_RECV_STACK 128
#define TASK_SERIAL_RECV_PRIORITY 1

#define TASK_VIT_READ_STACK 128
#define TASK_VIT_READ_PRIORITY 3

#define TASK_HOUSE_KEEP_STACK 128
#define TASK_HOUSE_KEEP_PRIORITY 0

#define TASK_MODE_SWITCH_STACK 128
#define TASK_MODE_SWITCH_PRIORITY 0

/--------------------------------Global Variables---------------------------/

/*

• This Queue will be used to collect data from various
• sensor and send to host.
  */
  QueueHandle_t SerialDataQueue;

/----------------------------------Functions--------------------------------/

void setup()
{

/*

• Settings for different IO pins according to its uses and their defualt
• states.
  */
  pinMode(PIN_SPI_CS_ADC, OUTPUT);
  digitalWrite(PIN_SPI_CS_ADC, HIGH);
  pinMode(PIN_SPI_CS_DAC, OUTPUT);
  digitalWrite(PIN_SPI_CS_DAC, HIGH);

/*

• Settings for SPI bus these are choosen common for ADC(MCP3204T)
• and DAC(MCP4921) as they exists in same bus
  */
  SPI.begin();
  SPI.setBitOrder(MSBFIRST); //MSB goes first out
  SPI.setClockDivider(SPI_CLOCK_DIV8); //2Mhz SPI clock

/*

• Settings for I2C bus to communicate with Digital POT(MCP4651T)
  */
  // Wire.begin();
  // Wire.setClock(I2C_CLK_RATE);

/*

• Configure serial port to communicate with host.
  */
  Serial.begin(SERIAL_BAUD_RATE);

SerialDataQueue = xQueueCreate(QUEUE_SERIAL_SEND_DEPTH,
QUEUE_SERIAL_SEND_BYTE_MAX_SIZE);
if (SerialDataQueue != NULL)
{
xTaskCreate(TaskSerialSend, "Serial Data Send Task",
TASK_SERIAL_SEND_STACK, NULL, TASK_SERIAL_SEND_PRIORITY,
NULL);
xTaskCreate(TaskSerialReceive, "Serial Recv Command Task",
TASK_SERIAL_RECV_STACK, NULL, TASK_SERIAL_RECV_PRIORITY,
NULL);
xTaskCreate(TaskVITRead, "Read Volt Current Temp Task",
TASK_VIT_READ_STACK, NULL, TASK_VIT_READ_PRIORITY, NULL);
xTaskCreate(TaskHouseKeep, "House Keeping Task", TASK_HOUSE_KEEP_STACK,
NULL, TASK_HOUSE_KEEP_PRIORITY, NULL);
xTaskCreate(TaskModeSwitch, "Mode Switching Task", TASK_MODE_SWITCH_STACK,
NULL, TASK_MODE_SWITCH_PRIORITY, NULL);
}

}

/---------------------------------------------------------------------------/

void loop()
{
}

/---------------------------------------------------------------------------/

//void writePot(uint8_t address, uint8_t potChannel, uint16_t val)
//{
// Wire.beginTransmission(address);
// Wire.write((potChannel & 3) << 4 | ((val >> 8) & 3));
// Wire.write(val & 0xFF);
// Wire.endTransmission();
//}

/---------------------------------------------------------------------------/

/**

• Serial Send task.
• Prints the received items from the queue to the serial monitor.
  /
  void TaskSerialSend(void * pvParameters)
  {
  uint8_t buf[6];
  /*
• Wait for serial port to connect. Needed for native USB, on LEONARDO, MICRO,
• YUN, and other 32u4 based boards.
  */
  while (!Serial)
  {
  vTaskDelay(1);
  }

for(;;)
{
if (xQueueReceive(SerialDataQueue, buf, portMAX_DELAY) == pdPASS)
{
Serial.write(buf, QUEUE_SERIAL_SEND_BYTE_MAX_SIZE);
}
}
}

/---------------------------------------------------------------------------/

/**

• Read data from different ADC channels and send as Voltage, Current and
• Temperature. The data is send to Queue SerialDataQueue this is directly send
• to host without processing.
  */
  void TaskVITRead(void * pvParameters)
  {
  char sTemperature[QUEUE_SERIAL_SEND_BYTE_MAX_SIZE]={'T','0',0x00,0x00,'\n'};
  char sADC_V[QUEUE_SERIAL_SEND_BYTE_MAX_SIZE]={'V','0',0x00,0x00,'\n'};
  char sADC_C[QUEUE_SERIAL_SEND_BYTE_MAX_SIZE]={'C','0',0x00,0x00,'\n'};

uint16_t *pTemperature = (uint16_t *)&(sTemperature[2]);

for(;;)
{
vTaskSuspendAll(); // Suspend task switching until sensor read is complete.
/Read Temperature/
pTemperature = analogRead(PIN_TEMP_SENSOR);
/

• Byte 1.On Sending Byte 1 response will be 'X','X','X','X','X','X','X','X' where X is dont

• care.

• Byte 1 send definition

• ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

• |b7:0|b6:0|b5:0|b4:0|b3:0|b2:1 start bit|b1:1 single/diff|b0:0 dnt care|

• ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

• Byte 2.On Sening Byte 2 response is 'X','X','X','N','B11','B10','B9','B8' where N is null

• byte and B11 is signaficant bit and so on.

• Byte 2 send defenition

• ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

• |b7:chan_s1|b6:chan_s0|b5:0 dnt care|b4:0 dnt care|b3:0 dnt care|b2:0 dnt care|b1:0 dnt care|b0:0 dnt care|

• '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

• Byte 3.On Sending Byte 3 response is 'B7','B6','B5','B4','B3','B2','B1','B0'

• Byte 3 send definition

• ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

• |b7:0 dnt care|b6:0 dnt care|b5:0 dnt care|b4:0 dnt care|b3:0 dnt care|b2:0 dnt care|b1:0 dnt care|b0:0 dnt care|

• '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

• ,,,,,,,,,,,,,,,,,,,,,,,,,

• |chan_s1|chan_s0|channel|

• '''''''''''''''''''''''''

• | 0 | 0 | 0 |

• '''''''''''''''''''''''''

• | 0 | 1 | 1 |

• '''''''''''''''''''''''''

• | 1 | 0 | 2 |

• '''''''''''''''''''''''''

• | 1 | 1 | 3 |

• '''''''''''''''''''''''''
  */
  /Read Voltage/
  digitalWrite(PIN_SPI_CS_ADC, LOW);
  SPI.transfer(0x18); //Refer the above commment for detail of command byte.
  sADC_V[3] = SPI.transfer(0x00); // First byte would be MSB from ADC channel 0
  sADC_V[2] = SPI.transfer(0x00); // Second byte would be LSB from ADC
  digitalWrite(PIN_SPI_CS_ADC, HIGH);

     /*Read Current*/
  

  digitalWrite(PIN_SPI_CS_ADC, LOW);
  SPI.transfer(0x18);
  sADC_C[3] = SPI.transfer(0x40);// First byte would be MSB from ADC channel 1
  sADC_C[2] = SPI.transfer(0x00);
  digitalWrite(PIN_SPI_CS_ADC, HIGH);

  xTaskResumeAll(); // Resume normal operation as sensor read is completed

  xQueueSend(SerialDataQueue, &sTemperature, portMAX_DELAY);
  xQueueSend(SerialDataQueue, &sADC_V, portMAX_DELAY);
  xQueueSend(SerialDataQueue, &sADC_C, portMAX_DELAY);
  vTaskDelay(1);
  }
  }

/---------------------------------------------------------------------------/

void TaskSerialReceive(void * pvParameters)
{
for(;;)
{
vTaskDelay(1000);
}
}

/---------------------------------------------------------------------------/

void TaskHouseKeep(void * pvParameters)
{
for(;;)
{
vTaskDelay(1000);
}
}

/---------------------------------------------------------------------------/

void TaskModeSwitch(void * pvParameters)
{
for(;;)
{
vTaskDelay(1000);
}
}

/---------------------------------------------------------------------------/
Code 2
#include <SPI.h>
#include <Wire.h>

#define QUEUE_SERIAL_SEND_DEPTH 10
#define QUEUE_SERIAL_SEND_BYTE_MAX_SIZE 5

#define TASK_SERIAL_SEND_STACK 128
#define TASK_SERIAL_SEND_PRIORITY 2
#define TASK_DATA_SEND_STACK 128
#define TASK_DATA_SEND_PRIORITY 1

#define SERIAL_BAUD_RATE 9600

#include <Arduino_FreeRTOS.h>
#include <queue.h>>

QueueHandle_t SerialDataQueue;

void setup() {
Serial.begin(SERIAL_BAUD_RATE);

SerialDataQueue = xQueueCreate(QUEUE_SERIAL_SEND_DEPTH,
QUEUE_SERIAL_SEND_BYTE_MAX_SIZE);
if (SerialDataQueue != NULL)
{
xTaskCreate(TaskSerialSend, "Serial Data Send Task",
TASK_SERIAL_SEND_STACK, NULL, TASK_SERIAL_SEND_PRIORITY,
NULL);
xTaskCreate(TaskDataSend, "Serial Data Send Task",
TASK_DATA_SEND_STACK, NULL, TASK_DATA_SEND_PRIORITY,
NULL);
}

}

void loop() {
// put your main code here, to run repeatedly:

}

void TaskSerialSend(void * pvParameters)
{
uint8_t buf[6];

while (!Serial)
{
vTaskDelay(1);
}

for (;;)
{
if (xQueueReceive(SerialDataQueue, buf, portMAX_DELAY) == pdPASS)
{
Serial.write(buf, QUEUE_SERIAL_SEND_BYTE_MAX_SIZE);
}
}
}

void TaskDataSend(void * pvParameters)
{
uint8_t buf[] = "HAI00";

while (!Serial)
{
vTaskDelay(1);
}

for (;;)
{
xQueueSend(SerialDataQueue, buf, portMAX_DELAY);
}
}
I was trying to interface atmega328 with MCP4651T Digital pot working with I2C(code 1). I find weird that including Wire.h make my scheduler stopped working. The device is working fine without any problem with Code 2. I don't know what is causing this issue. Could you please assist me.

[feilipu]

I don't have time today to look at this in detail and try to replicate, but my first guess is that you've run out of RAM, and somewhere a stack is being overwritten.

The ATmega328 doesn't have much RAM to go around. If you have a ATmega2650, then try that to see if the problem doesn't show.

Also try being more conservative with some of the stack sizes for your null tasks (HouseKeep, SerialReceive, ModeSwitch) currently, say around 96 bytes. See if that changes anything.

Unrelated but similar, I once tried to build a NFC sniffer, and write the results to a SD card. There was enough RAM to do either thing, but not both at the same time. That was the inspiration for the ATmega1284p Goldilocks, with 16kB of RAM.

[JBRO8081]

As you said I was running out of the stack. I didn't mount an LED on pin 13 to get a visual indication.Sorry my bad.