dfx see notes below.
// #define KEY_FUNC_SEL PIND4 // --> first key (Port D pin 4)
// in WinAvr PIND4 is a bit position and is equal to 4
#define KEY_FUNC_SEL (1<<PIND4) // resolves to 0x10
ISR(PCINT3_vect) { // FUNCTION KEY
uint8_t i;
// i = PORTD;
// PORTD is the output register for PORTD. To read the port pin state you
need to read PIND
i = PIND;
if ((i & FUNC_SEL_KEY) > 0) { // Test a key
LED_PORT |= (1 << PORTB0);
_delay_ms(100);
LED_PORT &= ~(1 << PORTB0);
_delay_ms(300);
}
// reti(); <- this will mess up the stack because
// the compiler handles restoring registers and the return from interrupt for
you.}
Matt
________________________________
From: dfx <d...@dfx.it>
To: avr-gcc-list@nongnu.org
Sent: Tuesday, January 14, 2014 8:54 AM
Subject: [avr-gcc-list] Simple but wrong code
Please consider this code:
#define KEY_PORT PORTD
#define KEY_DDR DDRD
#define KEY_FUNC_SEL PIND4 // --> first key (Port D pin 4)
....
#define LED_PORT PORTB // Test led, to see action on keypress
....
#define FUNC_SEL_KEY 0x10 // First function --> first key (Port D pin 4)
....
int main() {
init();
while (1) {
// waits indefinitely for keypress
}
return (EXIT_SUCCESS); // Never reached
}
void init() {
cli();
LED_DDR |= (1 << DDB0); // Led out Port B pin 0
KEY_PORT |= (1 << PORTD4) ; // pull-up resistor
PCICR |= (1 << PCIE3); // Enable interrupts on PORTD (PCINT31:24)
PCMSK0 = 0X00; // Disable unnecessary
PCMSK1 = 0X00;
PCMSK2 = 0X00;
PCMSK3 |= (1 << PCINT28); // Enable key
sei();
}
ISR(PCINT3_vect) { // FUNCTION KEY
uint8_t i;
i = PORTD;
if ((i & FUNC_SEL_KEY) > 0) { // Test a key
LED_PORT |= (1 << PORTB0);
_delay_ms(100);
LED_PORT &= ~(1 << PORTB0);
_delay_ms(300);
}
reti();
}
ISR(BADISR_vect) {
LED_PORT |= (1 << PORTB0);
_delay_ms(200);
LED_PORT &= ~(1 << PORTB0);
_delay_ms(200);
LED_PORT |= (1 << PORTB0);
_delay_ms(200);
LED_PORT &= ~(1 << PORTB0);
_delay_ms(200);
LED_PORT |= (1 << PORTB0);
_delay_ms(200);
LED_PORT &= ~(1 << PORTB0);
_delay_ms(200);
reti();
}
the button has a capacitor 1uF for debouncing (together with the pull-up
from 10 kohm)
The result is the following:
when I press the button, are generated two flashes (instead of one),
and when I release the button are generated two more flashes.
Similarly, If I comment out the routine (ISR PCINT3_vect),
the error routine (ISR BADISR_vect) generates double of the expected
flashes.
Can anyone help me to understand the problem?
Thank you very much.
--
Domenico
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