Problems using Timer and OS_Delay

[Syed Akbar]

Hello Aek,

In my Salvo program, i have two tasks. and 1 binary semaphore. Task1 is the highest priority task. But Task1 can be run only when a timer with 20ms(50Hz) expires. Task1 will signal task2. Based on tutorial5, i have used the following timer.
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void)
{
CCR0 += 10000;
OSTimer();
}
It is explained that this is 10ms system timer. therefore for 20ms i have used
OS_Delay(2,acb302_conversion_label);
I have used this statement in the task1 at the end after signalling binary semaphore.

As per the general rule, it shld context switch and the task2 which is waiting the semaphore shld run. Unfortuntely, it breaks here without going to the next task.

Hopefully, you followed the description. Can you please elucidate me what can be the problem. I shall provide with further details, if you require any.

Thank you very much
-Syed Akbar

------------------
Akbar

[aek]

You appear to be doing things right -- can you post the entire main.c so I can see your tasks?

------------------

[aek]

Hello Syed.

The problem is that you have not created infinite loops inside your tasks. What you need is e.g.

code:

---

void acb302_conversion(void)
{
  while (1)
  {
    start_conv_acb302(); // Starts ADC10 Conversion
    ACB302_conv(); // Starts conversions
    OSSignalBinSem(BINSEM1_P);
    OS_Delay(2,acb302_conversion_label); // delays the task by 2*10ms= 20ms(50Hz)
  }
}

---

Without these infinite loops, program execution "falls out" of each task at the end, and the program's behavior is undefined.

------------------

[This message has been edited by aek (edited November 09, 2005).]

[Syed Akbar]

Thank you very much. My problem is solved.
-Syed Akbar

[Syed Akbar]

Thank you very much. I am hereby posting my main.c I have used some functions from an Assembly program using the concept of mixing C and Assembly.
- Syed Akbar

code:

---

#include <main.h>
#include <salvo.h>
#include <msp430x12x2.h>
#include "mytypes.h"                           // My own things...
const UINT32 BoardID0 @ 0xE000 = 0x01234567;
const UINT32 BoardID1 @ 0xE004 = 0x89abcdef;
                                                  // declarations for functions used from ACB302_1.s43
extern void init_acb302(void);
extern void start_conv_acb302(void);
extern void ACB302_conv(void);
extern void ACB302_vektorbetrag(void);
#define TASK_ACB302_CONVERSION          OSTCBP(1) // Task 1 definition
#define TASK_RESULTANT_VECTOR           OSTCBP(2) // Task 2 definition
//#define TASK_DISPLAY_VIBRATIONS         OSTCBP(3) // Task 3 definition

#define BINSEM1_P                       OSECBP(1) // Event 1: Binary Semaphore

#define PRIO_ACB302_CONVERSION             1      // Priority of Task 1
#define PRIO_RESULTANT_VECTOR              2      // Priority of Task 2
//#define PRIO_DISPLAY_VIBRATIONS            3      // Priority of Task 3

_OSLabel(acb302_conversion_label)                 // Task 1 label for context switch
_OSLabel(resultant_vector_label)                  // Task 2 label for context switch
//_OSLabel(display_vibrations_label)                // Task 3 label for context switch
//////////////////////////////////////////////////////////////
// Name: Set_DCO
// Description: Sets the DCO and controls speed using TimerA SW FLL
// Parameter: -
// Returns: -
//////////////////////////////////////////////////////////////
void Set_DCO (void)                                       // Set DCO to selected frequency
{
#define DELTA 977                                         // target DCO= DELTA*(4096) = 4Mhz
//#define DELTA 900                                       // target DCO = DELTA*(4096) = 3686400
//#define DELTA 256                                       // target DCO = DELTA*(4096) = 1048576
//#define DELTA 70                                        // target DCO = DELTA*(4096) = 286720
  unsigned int Compare, Oldcapture = 0;
  BCSCTL1 |= DIVA_3;                                      // ACLK= LFXT1CLK/8
  CCTL2 = CM_1 + CCIS_1 + CAP;                            // CAP, ACLK
  TACTL = TASSEL_2 + MC_2 + TACLR;                        // SMCLK, cont-mode, clear
  while (1)
  {
    while (!(CCIFG & CCTL2));                             // Wait until capture occured
    CCTL2 &= ~CCIFG;                                      // Capture occured, clear flag
    Compare = CCR2;                                       // Get current captured SMCLK
    Compare = Compare - Oldcapture;                       // SMCLK difference
    Oldcapture = CCR2;                                    // Save current captured SMCLK
    if (DELTA == Compare) break;                          // If equal, leave "while(1)"
    else if (DELTA < Compare)                             // DCO is too fast, slow it down
    {
      DCOCTL--;
      if (DCOCTL == 0xFF)
      {
        if (!(BCSCTL1 == (XT2OFF + DIVA_3)))
        BCSCTL1--;                                        // Did DCO roll under?, Sel lower RSEL
      }
    }
    else
    {
      DCOCTL++;
      if (DCOCTL == 0x00)
        {
          if (!(BCSCTL1 == (XT2OFF + DIVA_3 + 0x07)))
          BCSCTL1++;                                      // Did DCO roll over? Sel higher RSEL
        }
    }
  }
  CCTL2 = 0;                                              // Stop CCR2
  TACTL = 0;                                              // Stop Timer_A
  BCSCTL1 &= ~0x30;                                       // Set ACLK Divider to 0
  BCSCTL2 = 0;                                            // MCLK = SMCLK = DCOCLK
}//Set_DCO

void acb302_conversion(void)
{
    start_conv_acb302();                                  // Starts ADC10 Conversion
    ACB302_conv();                                        // Starts conversions
    OSSignalBinSem(BINSEM1_P);
    OS_Delay(2,acb302_conversion_label);                  // delays the task by 2*10ms= 20ms(50Hz)
}
void resultant_vector(void)
{
  ACB302_vektorbetrag();                                  // calculates the resultant vector
  P1OUT ^= 0x01;                                          // Toggle P1.0 using XOR
  OS_WaitBinSem(BINSEM1_P, OSNO_TIMEOUT, resultant_vector_label);
}
//void display_vibrations(void)
//{
//}

//-----------------------------------------------------------------------------------------
void main()
//-----------------------------------------------------------------------------------------
{
  Init();                                                // For Device Initialization
  OSInit();                                              // Initializes all of Salvo's data structures,
                                                         // pointers, and counters.
  InitPORT();                                            // Port Initialization
  WDTCTL=WDTPW+WDTHOLD;                                  // stop WD
  P1OUT = 0x00;                                          // Set P1 to output direction
  P1DIR = 0x03;
  Set_DCO();
  P2DIR |= 0x08;                                        // Turn on Sensor switch
  P2OUT |= 0x08;
  init_acb302();                                        // Initializes ACB302 and Enables adc10_irq interrupt function
                                                        // which reads x,y and z axes.

                                                        // Create Tasks
  OSCreateTask(acb302_conversion, TASK_ACB302_CONVERSION, PRIO_ACB302_CONVERSION);
  OSCreateTask(resultant_vector, TASK_RESULTANT_VECTOR, PRIO_RESULTANT_VECTOR);
//  OSCreateTask(display_vibrations, TASK_DISPLAY_VIBRATIONS,PRIO_DISPLAY_VIBRATIONS);

  OSCreateBinSem(BINSEM1_P, 0);                        // Creates Binary Semaphore
  OSEi();                                              // Enables Interrupts
  for(; ;)
    OSSched();                                         // Multitasking
}

                                                        // Interrupt Vecator for Timer
                                                        // 10ms System Timer at a frequency of 100Hz
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void)
{
    CCR0 += 10000;
    OSTimer();
}

---

------------------
Akbar

[This message has been edited by aek (edited November 09, 2005).]