Reentrancy problem - Electronic Circuits Projects Diagrams Free

tattee · 29th January 2009, 09:46 AM

I got this error using MikroC "Reentrancy not allowed function[Spi_Write] called in both main and interrupt threads". I used PIC16F873 and having the SPI communication at the moment.

Why do I get this problem? How will I solve this? I really have to call some functions inside the interrupt to perform some task.

3v0 · 29th January 2009, 10:00 AM

Quote:

Originally Posted by tattee

I got this error using MikroC "Reentrancy not allowed function[Spi_Write] called in both main and interrupt threads". I used PIC16F873 and having the SPI communication at the moment.

Why do I get this problem? How will I solve this? I really have to call some functions inside the interrupt to perform some task.

A Reenterant function is one that can be called when it is already active. In the case of your interrupt routine I think you are getting interrupts while you are still inside your routine. This should not happen because the interrupt should be off while in the interupt service function.

Post the code. Use [code] ... your code here [/code] to keep the code formated.

Pommie · 29th January 2009, 10:02 AM

Think what would happen if an interrupt came along whilst the main code was half way through transmitting a byte. Change your code so that all the SPI stuff is in either the main code or the interrupt. If your unsure how to do this then post your code (put [code] before it and [/code] after it).

Mike.

tattee · 29th January 2009, 10:20 AM

Im trying to communicate between PIC16F873 and a digital potentiometer using SPI communication. I attached the code below.

Pommie · 29th January 2009, 10:44 AM

Change it so your interrupt routine sets a variable called pot to 0/1 and change move_pot to be,

Code:

void move_pot()
{
  if(Pot==1)
    Spi_Write(0xff); 
  else
    Spi_Write(0x00); 
  SPI_CS_POT = 0;
  PORTC.F0 = 1;
  Spi_Write(0b01);                                 
  Spi_Write(0x82);                                 //Set digital potentiometer to midpoint (5K)
  SPI_CS_POT = 1;
}

Mike.

tattee · 29th January 2009, 10:50 AM

WoW!! That's a simple but great solution Mike! THanks! I'll try this out!

tattee · 29th January 2009, 10:57 AM

By the way, will it interrupt the main program? Do I have to put the mov_pot function to a loop so it does the changes as soon as the interrupt is activated?

Pommie · 29th January 2009, 11:24 AM

Without knowing the hardware I don't know if you need to call it repeatedly. An alternative way to do it would be,

Code:

void main()
{

  init_pic();
  init_timer0();
  Spi_Init_Advanced(MASTER_OSC_DIV4,
                    DATA_SAMPLE_MIDDLE,
                    CLK_IDLE_LOW,
                    LOW_2_HIGH);
 
  move_pot();
  
  INTCON = 0b10011000;
  
  do {
    if(Pot==1)
      Spi_Write(0xff); 
    else
      Spi_Write(0x00); 

     } while(1);
 }

Or, if calling the SPI function repeatedly is a problem then set Pot to 1/2 and change the code to be,

Code:

    if(Pot==1){
      Spi_Write(0xff); 
      Pot=0;
    }else if(Pot==2){
      Spi_Write(0x00);
      Pot=0;
    }

Mike.

tattee · 29th January 2009, 12:46 PM

Thanks Mike,

I guess the do-while will do the job. Thanks again!

russ_hensel · 29th January 2009, 02:40 PM

This is an issue with BoostC as well so perhaps with many microcontroller Cs.
In any case the code in an interrups should be as short as possible. No delays.... State variables as suggested above let you do the slow stuff in the main line.

tattee · 9th February 2009, 05:49 AM

Hi Guys!

I just wanna update you on my project. So, far the suggestion made by Pommie has had great success. Thanks again Pommie!

Now, Ive run into another problem.. Here's the code:

Code:

void Interrupt()
{
  if(INTCON.INTF)
  {
       SWITCH = W ;
       PORTA.F1 = 1;
       INTCON.INTF = 0;
  }
  else if(INTCON.RBIF)
  {
      if(PORTB.F5 == 0)                 
      {
         SWITCH = X;
         INTCON.RBIF = 0;
      }
      else if(PORTB.F6 == 0)             
      {
         SWITCH = Y;
         INTCON.RBIF = 0;
      }
      else if(PORTB.F7 == 0)
      {
         SWITCH = X;
         INTCON.RBIF = 0;
      }
   }
}

void main()
{ 
   init_all();

   do {
        switch(SWITCH)
        {
          case X:
                  INTCON.GIE = 0;
                 //do something here           
                 INTCON = 0b10011000;
          break;

          case Y:
                 INTCON.GIE = 0;
                 //do something here   
                 INTCON = 0b10011000;
          break;

          case Z:
                 INTCON.GIE = 0;
                 //do something here   
                 INTCON = 0b10011000;
          break;
          
          case W:
                 INTCON.GIE = 0;
                 PORTA.F0 = 1;
                 INTCON = 0b10011000;
          break;
          }
     } while(1);

For the INTCON.RBIF part, everything worked fine. The code reacts exactly as expected everytime PORTS 5,6,and 7 are interrupted.. The problem comes when I try to interrupt the INTCON.INTF. my code doesn't interrupt at all. why is this happening?

take note that when I try to interrupt INTCON.INTF, the PORTA.F1 = 1; is executed but not the case W: statement.

Pommie · 9th February 2009, 06:02 AM

What are SWITCH, W, X, Y and Z defined as?

Mike.

tattee · 9th February 2009, 06:25 AM

here is the edited code:

Code:

#define VOLUME_UP            1
#define VOLUME_DOWN       2
#define DIAL              3
#define DTMF_RECIEVED      4

unsigned short SWITCH = 0;

void Interrupt()
{
  if(INTCON.INTF)
  {
       SWITCH = W ;
       PORTA.F1 = 1;
       INTCON.INTF = 0;
  }
  else if(INTCON.RBIF)
  {
      if(PORTB.F5 == 0)                 
      {
         SWITCH = X;
         INTCON.RBIF = 0;
      }
      else if(PORTB.F6 == 0)             
      {
         SWITCH = Y;
         INTCON.RBIF = 0;
      }
      else if(PORTB.F7 == 0)
      {
         SWITCH = X;
         INTCON.RBIF = 0;
      }
   }
}

void main()
{ 
   init_all();

   do {
        switch(SWITCH)
        {
          case X:
                  INTCON.GIE = 0;
                 //do something here           
                 INTCON = 0b10011000;
          break;

          case Y:
                 INTCON.GIE = 0;
                 //do something here   
                 INTCON = 0b10011000;
          break;

          case Z:
                 INTCON.GIE = 0;
                 //do something here   
                 INTCON = 0b10011000;
          break;
          
          case W:
                 INTCON.GIE = 0;
                 PORTA.F0 = 1;
                 INTCON = 0b10011000;
          break;
          }
     } while(1);

Pommie · 9th February 2009, 06:37 AM

I still can't see where W, X, Y & Z are defined.

Mike.

tattee · 9th February 2009, 06:40 AM

oh im sorry, i wasn't able to edit the line.. here it is:

Code:

#define X            1
#define Y      2
#define Z             3
#define W      4

unsigned short SWITCH = 0;

void Interrupt()
{
  if(INTCON.INTF)
  {
       SWITCH = W ;
       PORTA.F1 = 1;
       INTCON.INTF = 0;
  }
  else if(INTCON.RBIF)
  {
      if(PORTB.F5 == 0)                 
      {
         SWITCH = X;
         INTCON.RBIF = 0;
      }
      else if(PORTB.F6 == 0)             
      {
         SWITCH = Y;
         INTCON.RBIF = 0;
      }
      else if(PORTB.F7 == 0)
      {
         SWITCH = X;
         INTCON.RBIF = 0;
      }
   }
}

void main()
{ 
   init_all();

   do {
        switch(SWITCH)
        {
          case X:
                  INTCON.GIE = 0;
                 //do something here           
                 INTCON = 0b10011000;
          break;

          case Y:
                 INTCON.GIE = 0;
                 //do something here   
                 INTCON = 0b10011000;
          break;

          case Z:
                 INTCON.GIE = 0;
                 //do something here   
                 INTCON = 0b10011000;
          break;
          
          case W:
                 INTCON.GIE = 0;
                 PORTA.F0 = 1;
                 INTCON = 0b10011000;
          break;
          }
     } while(1);

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29th January 2009, 09:46 AM	#1
tattee	Reentrancy problem I got this error using MikroC "Reentrancy not allowed function[Spi_Write] called in both main and interrupt threads". I used PIC16F873 and having the SPI communication at the moment. Why do I get this problem? How will I solve this? I really have to call some functions inside the interrupt to perform some task.

29th January 2009, 10:02 AM	#3
Pommie	Think what would happen if an interrupt came along whilst the main code was half way through transmitting a byte. Change your code so that all the SPI stuff is in either the main code or the interrupt. If your unsure how to do this then post your code (put [code] before it and [/code] after it). Mike.

29th January 2009, 10:44 AM	#5
Pommie	Change it so your interrupt routine sets a variable called pot to 0/1 and change move_pot to be, Code: void move_pot() { if(Pot==1) Spi_Write(0xff); else Spi_Write(0x00); SPI_CS_POT = 0; PORTC.F0 = 1; Spi_Write(0b01); Spi_Write(0x82); //Set digital potentiometer to midpoint (5K) SPI_CS_POT = 1; } Mike.

29th January 2009, 10:50 AM	#6
tattee	WoW!! That's a simple but great solution Mike! THanks! I'll try this out!

29th January 2009, 10:57 AM	#7
tattee	By the way, will it interrupt the main program? Do I have to put the mov_pot function to a loop so it does the changes as soon as the interrupt is activated?

29th January 2009, 12:46 PM	#9
tattee	Thanks Mike, I guess the do-while will do the job. Thanks again!

29th January 2009, 02:40 PM	#10
russ_hensel	BoostC too This is an issue with BoostC as well so perhaps with many microcontroller Cs. In any case the code in an interrups should be as short as possible. No delays.... State variables as suggested above let you do the slow stuff in the main line.

9th February 2009, 06:02 AM	#12
Pommie	What are SWITCH, W, X, Y and Z defined as? Mike.

9th February 2009, 06:37 AM	#14
Pommie	I still can't see where W, X, Y & Z are defined. Mike.