c - ISR + Code，将计数代码与 ISR 例程集成

Question

我有一段用于 PIC 设备的 C 代码，它按照预定义的模式驱动 4 个独立的继电器，每个继电器通过计数次数和发生频率来单独设置。这种模式会无限延续，但发现标准delay_ms 上的计时不够准确。我希望将其转换为 ISR 例程，我附上下面依赖于标准延迟的代码供您细读，我主要关心的是如何将此代码抽象为 ISR，因为我知道不要将所有这些代码都粘贴在实际的 ISR 例程中，任何非常感谢您的建议。

__CONFIG(FOSC_XT & WDTE_OFF & PWRTE_OFF & MCLRE_OFF & CP_OFF & CPD_OFF &
        BOREN_OFF & CLKOUTEN_OFF & IESO_OFF & FCMEN_OFF);

//!!! use BORV_HI for latest PICC compiler
__CONFIG(WRT_OFF & PLLEN_OFF & STVREN_OFF & LVP_OFF);       

#define _XTAL_FREQ  4000000

unsigned long int Sample_Period =20;
unsigned long int Sample_Duration = 2;
unsigned long int Sample_ON = 0;
unsigned long int WriteTX_Period = 21;
unsigned long int WriteTX_Duration = 1; //  
unsigned long int WriteTX_ON = 0;
unsigned long int Depass_Period = 60; //every 7 days for depass event
unsigned long int Depass_Duration = 10 ; // depass for 120 seconds
unsigned long int Depass_ON = 0 ;
unsigned long int Depass_Counter = 0;
unsigned long int Sample_Counter = 0;
unsigned long int WriteTX_Counter = 0;
unsigned long int count = 0;
unsigned char input;
char data = 1;

void SkipLine(void){
    printf("\n");
    printf("\r");
}

void main() {
    INTCON = 0;                 // disable interrupts.
    ANSELA = 0x00;              // all digital IO
    ANSELB = 0x00;              // all digital IO
    TRISA = 0b00000000;         // Configure PORTA as output 
    PORTA = 0b00000111;         // Initialize PORTA, all load relays are off.
    ADCON0 = 7;                 // disables ADC
    CM1CON0 = 7;                // Disable analog comparators
    TRISB = 0b10111001;         // all outputs bar RB1/RX pin, and RB7 (Prog'd)

    init_comms();

    printf("\n");
    printf("\r");
    printf("*******************************");
    printf("\n");
    printf("\r");
    printf("*METROL RELAY CONTROLLER MK1.0*");
    printf("\n");
    printf("\r");
    printf("*******************************");
    printf("\n");
    printf("\r");

    printf("Default timings are :");
    printf("\n");
    printf("\r");
    printf("Sample Period = ");
    printf("%d seconds", Sample_Period);
    printf("\n");
    printf("\r");

    printf("\n");
    printf("\r");
    printf("Sample Duration = ");
    printf("%d seconds", Sample_Duration);
    printf("\n");
    printf("\r");

    printf("\n");
    printf("\r");
    printf("WriteTX Period = ");
    printf("%d seconds", WriteTX_Period);
    printf("\n");
    printf("\r");

    printf("\n");
    printf("\r");
    printf("WriteTX Duration = ");
    printf("%d seconds", WriteTX_Duration);
    SkipLine;

    printf("\n");
    printf("\r");
    printf("Depassivation Period (Days)= ");
    printf("%d Days", Depass_Period);
    printf("\n");
    printf("\r");
    printf("\n");
    printf("\r");
    printf("Depassivation Duration  = ");
    printf("%d seconds", Depass_Duration);
    printf("\n");
    printf("\r");

    if (RB7 == 1)
    {
        printf("requires set up");

        printf("\n");
        printf("\r");
        printf("\n");
        printf("\r");

        printf("Enter value for Sample Period in minutes <0-255> ");
        printf("\n");
        printf("\r");

        char str[50];

        printf("Enter a string : ");
        gets(str);

        printf("You entered: %s", str);
        int SamplePeriodVal;
        SamplePeriodVal = atoi(str);
        printf("Sample Period Value entered = %d\n", SamplePeriodVal);
    }

    printf("\n");
    printf("\r");
    printf("system already configured");
    printf("\n");
    printf("\r");

    unsigned int Sample_Period_Units;
    Sample_Period_Units = EEPROM_READ(0x00);
    printf("sample value held in first eeprom address 0x00 is %d", EEPROM_READ(0x00));

    printf("\n");
    printf("\r");
    printf("load profile starting.....");
    printf("\n");
    printf("\r");

    while (1) {
        printf("\n");
        printf("\r");
        printf("test!");
        printf("\n");
        printf("\r");

        __delay_ms(990);

        if (Sample_Counter >= Sample_Period){
            PORTA = 0b00000110; //set Sample relay ON

            Sample_ON++;

            if (Sample_ON > Sample_Duration){
                Sample_ON = 0;
                Sample_Counter = 0;
                PORTA = 0b00000111;

            }
        }

        if (WriteTX_Counter >= WriteTX_Period){
            PORTA = 0b00000100; //set Write relay ON

            WriteTX_ON++;

            if (WriteTX_ON > WriteTX_Duration){
                WriteTX_ON = 0;
                WriteTX_Counter = 0;
                PORTA = 0b00000111;

            }
        }

        if (Depass_Counter >= Depass_Period){
            PORTA = 0b00000011; //set Depass relay ON


            Depass_ON++;

            if (Depass_ON > Depass_Duration){
                Depass_ON = 0;
                Depass_Counter = 0;
                PORTA = 0b00000111;

            }
        }

        Sample_Counter++;
        WriteTX_Counter++;
        Depass_Counter++;
        count++;            // increment total count for system

        printf("\n");
        printf("\r");

        int SampleAct;
        SampleAct = RB3;
        printf("Port B sample value =%d  ", SampleAct);

        printf("\r");
        printf("\n");

        int WriteTXAct;
        WriteTXAct = RB4;
        printf("Port B WriteTX value =%d  ", WriteTXAct);

        printf("\r");
        printf("\n");

        int DepassAct;
        DepassAct = RB5;
        printf("Port B Depass value =%d  ", DepassAct);

        printf("\r");
        printf("\n");
        printf("%ld", count);

        int PortB_Val;

        PortB_Val = PORTB & 0b00111000;

        switch (PortB_Val)
        {

        case 0x28:
            RB6 = RB6;
            printf("\n");
            printf("\r");
            printf("Sample+Depass error");
            break;

        case 0x30:
            RB6 = RB6;
            printf("\n");
            printf("\r");
            printf("Write+Depass error");
            break;

        case 0x38:
            RB6 = RB6;
            printf("\n");
            printf("\r");
            printf("Write+Sample+Depass error");
            break;

        default:
            RB6 = !RB6;
        }
    }
}

Answer 1

您的代码仅取决于周期性计时器滴答声，因此总体思路是执行以下操作:

volatile static uint8_t tick;

ISR(TIMER_vec) /* whatever int vector is triggered by your timer */
{
    ++tick;
}


int main () {
    /* [...] */

    while (1)
    {
        uint8_t lasttick = 0;
        while (tick != lasttick)
        {
            lasttick = tick; /* or ++lasttick; for handling "missed" interrupts late */

            /*
             * do your periodic stuff here
             */
        }
        /* wait for next interrupt, e.g. by entering sleep state
           for AVR: */
        sleep_cpu();
    }
}

当然，您必须根据您的芯片安排定时器中断。如果事情变得更复杂，您可能会对some code I wrote感兴趣。使用 ISR 来填充事件队列。