Multitasking implimenting on PIC16F886 using Timer1

[Gopalkrishna.D]

Hi,

I am developing some application in PICDEM SYSTEM MANAGEMENT board using PIC16F886.
I am trying to impliment thread (multitasking) concept in my program using Timer1.
The below shown program works with MPLAB SIM perfectly.But when i impliment the same program on the demo board using PICkit3
debugger it is hanging(Timer1 Interrupt not occuring) hence i am not getting the multitasking. What might be the problem ?

and please let me know how to use CONFIG1 Register in PIC16F886.

The Program is given below......


Main.c


#include <htc.h>
#include <pic.h>
#include <stdio.h>
#include <stdlib.h>
#include "877_i2c.h"
#include "delay.h"

#ifndef _XTAL_FREQ
// Unless already defined assume 4MHz system frequency
// This definition is required to calibrate __delay_us() and __delay_ms()
#define _XTAL_FREQ 4000000
#endif

//task counters used to tell when a task is ready to be executed
//all these counters are incremented every time a 100ms interrupt happens
//every task has its own counter that is updated every time a 100ms interrupt happens
unsigned int task_counter=0;

unsigned int Btn_flag=0;

#define TASK_COUNTER_MAX 2 // task every 100ms
#define TRUE 1
#define FALSE 0

//#BYTE CONFIG1 = 0X2007

//Button definitions
#define ON_OFF 1
#define AUD_INPUT_SRC_SELCT 2
#define VOL_UP 3
#define VOL_DOWN 4
#define MUTE 5

volatile unsigned char task_enable=TRUE; //enables the task

void column_4();
void column_5();

void initPORTS ()
{
TRISA = 1; // Input for RA0 to RA7
TRISB = 0; // presently this port is not used
TRISC = 0; //set all ports as output
ANSEL = 0; //make all ports as digital I/O
ANSELH = 0;
PORTA = 0; // set all ports to low
PORTB = 0;
PORTC = 0;
}

void setup_multitasking(void)
{
//set up tmr1 to interrupt every 100ms
TMR1CS=0; // 0 - internal clock(Fosc/4) 1- External clk
T1CKPS0=0; //1:1 prescale value
T1CKPS1=0; //1:1 prescale value

/*We want to wait 200 clock cycles, or 100ms @ 8MHz (instructions are 1/4 speed of clock).
Timer 1 interrupts when it gets to 0xFFFF or 65535. Therefore, we set timer 1 to 65535
minus 2000 = 63535, then wait 2000 ticks until rollover at 65535. To test, use simulator
to find that its exactly correct*/

#define TICKS_BETWEEN_INTERRUPTS 2000 //2000
#define INTERRUPT_OVERHEAD 19 //19
#define TMR1RESET (0xFFFF-(TICKS_BETWEEN_INTERRUPTS-INTERRUPT_OVERHEAD))
#define TMR1RESET_HIGH TMR1RESET >> 8
#define TMR1RESET_LOW TMR1RESET & 0xFF
TMR1ON=0;
TMR1H=TMR1RESET_HIGH;
TMR1L=TMR1RESET_LOW;
TMR1ON=1;
TMR1IF=0;
TMR1IE=1;
PEIE=1;
GIE=1;
}

void interrupt ISR(void)
{
//one tick every 100ms at 8Mhz
if (TMR1IF)
{
//set up timer 1 again to interrupt 100ms in future
TMR1IF=0;
TMR1ON=0;
TMR1H=TMR1RESET_HIGH;
TMR1L=TMR1RESET_LOW;
TMR1ON=1;
task_counter++;
if (task_counter>=TASK_COUNTER_MAX) //high frequency task every 1 tick
{
task_counter=0;
if (task_enable==TRUE)
{
column_4();
column_5();
}
}
} //if (TMR1IF)
} //interrupt service routine

void column_4()
{
RA5 = 1; //make FP_CLOCK pin high
RC0 = 1; //make FP_STROBE pin high
unsigned int i=0,temp=0;
unsigned int col4_check = 0x08;

for (i=0;i<8;i++)
{
temp = col4_check;
if ((temp & 0x80) == 0x80)
{
temp = (temp << 1);
RC1 = temp;
}
}

if (RA2 == 1)
{
Btn_flag = AUD_INPUT_SRC_SELCT; //indicates "PAUSE" button is pressed
}

if (RA3 == 1)
{
Btn_flag = MUTE; //indicates "STOP" button is pressed
}

if (RA4 == 1)
{
Btn_flag = VOL_UP ; //indicates "FORWARD" button is pressed
}
}

void column_5()
{
RA5 = 1; //make FP_CLOCK pin high
RC0 = 1; //make FP_STROBE pin high
unsigned int i=0,temp1=0;
unsigned int col5_check = 04;

for (i=0;i<8;i++)
{
temp1 = col5_check;
if ((col5_check & 0x80) == 0x80)
{
temp1 = (temp1 << 1);
RC1 = temp1;
}
}

if (RA2 == 1)
{
Btn_flag = ON_OFF; //indicates "RECORD" button is pressed
}

if (RA4 == 1)
{
Btn_flag = VOL_DOWN; //indicates "REWIND" button is pressed
}
}

/******************************************************************************************/

void write_ext_eeprom(unsigned char address, unsigned char data)
{
i2c_start();
i2c_write(0xa0);
i2c_write(0x00);
i2c_write(address);
i2c_write(data);
__delay_ms(1);
i2c_stop();
__delay_ms(1);

}

/******************************************************************************************/

unsigned char read_ext_eeprom(unsigned char address)
{
unsigned char data;

i2c_start();
i2c_write(0xa0);
i2c_write(0x00);
i2c_write(address);
i2c_repStart();
i2c_write(0xa1);
data=i2c_read(0);
i2c_stop();
return(data);
}

/******************************************************************************************/
main()
{
unsigned char i;
unsigned char j;
unsigned char k;
unsigned char m;
int flag=1;

//OSCCON = 0x6D; //select 8Mhz internal clock

TMR1IF=0;
initPORTS () ;

i2c_init(); // init i2c

//setup_multitasking();

while(flag)
{
flag=0;
i=0;
j=0x05;

while(i<=2)
{
//write_ext_eeprom(i,j); // the memory and show it on leds,it shoaled be the same like the address
// __delay_ms(1);
RA2=1;
/* __delay_ms(100);
__delay_ms(100);
__delay_ms(100);
__delay_ms(100);
__delay_ms(100);
__delay_ms(100); */
RA2=0;
i++;
j++;
}

RA2=1;
RA4=1;
RB5=1;

/* __delay_ms(100);
__delay_ms(100);
__delay_ms(100);

__delay_ms(100);
__delay_ms(100);
__delay_ms(100);

__delay_ms(100);
__delay_ms(100);
__delay_ms(100); */

RA2=0;
RA4=0;
RB5=0;

i=0;
j=0x05;
while(i<=2)
{
// k=read_ext_eeprom(i); // the memory and show it on leds,it shoaled be the same like the address
//__delay_ms(1);

if(k==j)
{
RA4=1;
/* __delay_ms(100);
__delay_ms(100);
__delay_ms(100);
__delay_ms(100);
__delay_ms(100);
__delay_ms(100); */

RA4=0;
}
i++;
j++;
}

RA2=1;
RA4=1;
RB5=1;

/* __delay_ms(100);
__delay_ms(100);
__delay_ms(100);

__delay_ms(100);
__delay_ms(100);
__delay_ms(100);

__delay_ms(100);
__delay_ms(100);
__delay_ms(100); */

RA2=0;
RA4=0;
RB5=0;

}

OSCCON = 0x70;
setup_multitasking();
m=0;
while(1)
{m++;
switch(Btn_flag)
{
case ON_OFF:
{
//printf("ON_OFF button is pressed\r\n");
Btn_flag = 0;
}
break;

case AUD_INPUT_SRC_SELCT:
{
//printf("AUD_I/P_SRC_SELCT button is pressed\r\n");
Btn_flag = 0;
}
break;

case VOL_UP:
{
//printf("VOL_UP button is pressed\r\n");
Btn_flag = 0;
}
break;

case VOL_DOWN:
{
//printf("VOL_DOWN button is pressed\r\n");
Btn_flag = 0;
}
break;

case MUTE:
{
//printf("MUTE button is pressed\r\n");
Btn_flag = 0;
}
break;
}
}
}

 

[Kripton2035]

hello,

I have almost the same problem with one of my circuit...


the simulation works well, the hardware is known to be good, but the program in the real hardware does not work.
something get stucks in the interrupt mecanism and I can't explain why...

I know my hardware is good because I have done the program without interrupts and it works well but for me it cannot go fast enough

so I rewrote it with interrupts, the simulation is full ok, but nothing happens in the real hardware...

your problem seems the same as mine. I am almost sure the solution is somewhere in the interrupt system, but I havent found where (for now ..)

regards,

 

[malik_123]

cannot u guys use 18f series , it will not take much time to move ur firmware to the 18f series .

 

[Kripton2035]

cannot u guys use 18f series , it will not take much time to move ur firmware to the 18f series .

because there are no pic18 in a 8 pdip package ...