在 AVR 中处理多个 PCINT 的最佳方法

Question

我正在 Attiny85 上测试一些东西，并考虑了处理中断规则的最佳方法。我知道在中断处理程序中有很多代码是不好的，但我不确定是否有任何其他方法可以做到这一点。我希望我的主程序在 PCINT 上休眠和唤醒，PCINT 来自多个引脚（旋转编码器 A、b 和开关和接收 UART），所以我想在处理程序中有很多代码。

确定哪个引脚导致中断的代码如下所示

#include <avr/io.h>
#include <stdint.h>            // has to be added to use uint8_t
#include <avr/interrupt.h>    // Needed to use interrupts
volatile uint8_t portbhistory = 0xFF;     // default is high because the pull-up

int main(void)
{
    DDRB &= ~((1 << DDB0) | (1 << DDB1) | (1 << DDB2)); // Clear the PB0, PB1, PB2 pin
    // PB0,PB1,PB2 (PCINT0, PCINT1, PCINT2 pin) are now inputs

    PORTB |= ((1 << PORTB0) | (1 << PORTB1) | (1 << PORTB2)); // turn On the Pull-up
    // PB0, PB1 and PB2 are now inputs with pull-up enabled

    PCICR |= (1 << PCIE0);     // set PCIE0 to enable PCMSK0 scan
    PCMSK0 |= (1 << PCINT0);   // set PCINT0 to trigger an interrupt on state change 

    sei();                     // turn on interrupts

    while(1)
    {
    /*main program loop here */
    }
}

ISR (PCINT0_vect)
{
    uint8_t changedbits;

    changedbits = PINB ^ portbhistory;
    portbhistory = PINB;

    if(changedbits & (1 << PB0))
    {
    /* PCINT0 changed */
    }

    if(changedbits & (1 << PB1))
    {
    /* PCINT1 changed */
    }

    if(changedbits & (1 << PB2))
    {
    /* PCINT2 changed */
    }
}

然后在中断处理程序中的每个 if 语句中，都会有代码处理一些事情，比如这段代码，打开 Timer0

TCNT0 = 0; // Set counter to 0
OCR0A = SERIAL_BIT_TIME; // Call timer interrupt in middle of first bit
position = 0; // Reset position and data
TIMSK |= 1 << OCIE0A; // Enable interrupt for compare register A (timer interrupt)
TIFR |= 1 << OCF0A; // Clear timer interrupt flag to prevent it jumping directly there
PCMSK &= ~(1 << SERIAL_RECEIVE); // Disable pin change interrupt

或者使用 switch 输入，if 语句中的代码将是

if (lightState)
{
    dali.transmit(ADDRESS, OFF);
    lightState = 0;
} 
else
{
    dali.transmit(ADDRESS, ON);
    lightState = 1;
}

这会是一个愚蠢的解决方案吗？

Answer 1

volatile uint8_t flag;

int main(void)
{
    DDRB &= ~((1 << DDB0) | (1 << DDB1) | (1 << DDB2)); // Clear the PB0, PB1, PB2 pin
    // PB0,PB1,PB2 (PCINT0, PCINT1, PCINT2 pin) are now inputs

    PORTB |= ((1 << PORTB0) | (1 << PORTB1) | (1 << PORTB2)); // turn On the Pull-up
    // PB0, PB1 and PB2 are now inputs with pull-up enabled

    PCICR |= (1 << PCIE0);     // set PCIE0 to enable PCMSK0 scan
    PCMSK0 |= (1 << PCINT0);   // set PCINT0 to trigger an interrupt on state change 

    sei();                     // turn on interrupts

    while(1)
    {
        gotosleep();
        do
        {
            switch(flag)
            {
                case 1:
                    dosomething1();
                    break;
                case 2:
                    dosomething2();
                    break;
                case 3:
                    dosomething3();
                    break;
            }
        cli();
        flag = 0;
        sei();
        }while(flag); 

    }
}

ISR (PCINT0_vect)
{
    uint8_t changedbits;

    changedbits = PINB ^ portbhistory;
    portbhistory = PINB;

    if(changedbits & (1 << PB0))
    {
        flag = 1;
    }

    if(changedbits & (1 << PB1))
    {
        flag = 2;
    }

    if(changedbits & (1 << PB2))
    {
        flag = 3;
    }
}