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..External Interrupt..INT0

hello all,
I am working with AT89C51CC01 which based on 8051.
I had write one program of external interrupt. See the code as follows.

void ex0_isr (void) interrupt 0
{
        CCAP1H = 0x5A;  // 35% Duty Cycle
}
void main (void)
{

//Configure INT0 (external interrupt 0) to generate an interrupt on the falling-edge of /INT0 (P3.2).
//Enable the EX0 interrupt and then enable the global interrupt flag.

        CMOD = 0x02; // Setup PCA timer

        CL = 0x00;
        CH = 0x00;

        CCAP1H = 0x10; // 75% Duty Cycle
        CCAPM1 = 0x42; // Setup PCA module 1 in PWM mode.

        IT0 = 1;   //  falling edge on /INT0 (P3.2)
        EX0 = 1;   // Enable EX0 Interrupt
        EA = 1;    // Enable Global Interrupt Flag

        CR = 1; // Start PCA Timer.

        while (1)
        {
        }
}

In this code without interrupt Duty cycle of PWM signal is 75% and when interrupt occur then Duty cycle is 35%.
This program works perfectly.

Is there possible to after interrupt then after some time program run normally (Same like without interrupt).
For example i want after interrupt after 5 min i come again into the same program routin.

Please give ur suggestion related to this problem.

Thanks in advance

Parents

0 Shaik Piebe over 14 years ago in reply to ImPer Westermark

hello all,
Thanks for ur reply.

I have one another task to do with External interrupt
Just see the code

#include "reg_c51.h"

unsigned char ex0_count = 0;
unsigned char ex1_count = 0;

void ex0(void) interrupt 0
{
        ex0_count++; // Increment the counter
}
void ex1(void) interrupt 2
{
        ex1_count++; // Increment the counter
}
void main (void)
{
        IT0 = 1;   // Configure interrupt 0
        IT1 = 1;   // Configure interrupt 1
        EX0 = 1;   // Enable EX0 Interrupt
        EX1 = 1;   // Enable EX1 Interrupt
        EA = 1;    // Enable Global Interrupt Flag

        CMOD = 0x02; // Setup PCA timer

        CL = 0x00;
        CH = 0x00;

        if (ex0_count > ex1_count)
        {       CCAP1H = 0x5A; } // 35% Duty Cycle
        else if (ex0_count < ex1_count)
        {       CCAP1H = 0x99; } // 60% Duty Cycle
        else
        {       CCAP1H = 0x10; }  // 75% Duty Cycle

        CCAPM1 = 0x42; // Setup PCA module 0 in PWM mode.
        CR = 1; // Start PCA Timer.

        while (1)
        {}
}
This program runs but gives only else part which is 75% of PWM.

But i want to do like if first time external interrup occurs then both ex0_counter and ex1_counter start to increment..then when 2nd time interrupt occurs then stop the counter increment.
So after 2nd interrupt i have fix value in both counters.
In main i compare this counter values n generate PWM accourding to comparision.

In interrupt function i just write counter increment but i want if first time interrupt occurs then counter start to increment and when 2nd time interrupt occurs then stop the counter incrementation.


Can i give both situation for same interrupt..??
I don´t have any idea for this task.
Please give me ur idea or suggestion for this question.

Thanks in advance

Reply

0 Shaik Piebe over 14 years ago in reply to ImPer Westermark

hello all,
Thanks for ur reply.

I have one another task to do with External interrupt
Just see the code

#include "reg_c51.h"

unsigned char ex0_count = 0;
unsigned char ex1_count = 0;

void ex0(void) interrupt 0
{
        ex0_count++; // Increment the counter
}
void ex1(void) interrupt 2
{
        ex1_count++; // Increment the counter
}
void main (void)
{
        IT0 = 1;   // Configure interrupt 0
        IT1 = 1;   // Configure interrupt 1
        EX0 = 1;   // Enable EX0 Interrupt
        EX1 = 1;   // Enable EX1 Interrupt
        EA = 1;    // Enable Global Interrupt Flag

        CMOD = 0x02; // Setup PCA timer

        CL = 0x00;
        CH = 0x00;

        if (ex0_count > ex1_count)
        {       CCAP1H = 0x5A; } // 35% Duty Cycle
        else if (ex0_count < ex1_count)
        {       CCAP1H = 0x99; } // 60% Duty Cycle
        else
        {       CCAP1H = 0x10; }  // 75% Duty Cycle

        CCAPM1 = 0x42; // Setup PCA module 0 in PWM mode.
        CR = 1; // Start PCA Timer.

        while (1)
        {}
}
This program runs but gives only else part which is 75% of PWM.

But i want to do like if first time external interrup occurs then both ex0_counter and ex1_counter start to increment..then when 2nd time interrupt occurs then stop the counter increment.
So after 2nd interrupt i have fix value in both counters.
In main i compare this counter values n generate PWM accourding to comparision.

In interrupt function i just write counter increment but i want if first time interrupt occurs then counter start to increment and when 2nd time interrupt occurs then stop the counter incrementation.


Can i give both situation for same interrupt..??
I don´t have any idea for this task.
Please give me ur idea or suggestion for this question.

Thanks in advance

Children

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