Re: Simple but wrong code

Hi John,

you're absolutely right. In fact the second pair of flash appears when I 
leave the key.

But, you know, how I can avoid this behavior?
I read the manual, but I have not found anything about it, except for 
INT2: 0 I seem to be more flexible.

There remains the problem of the duplication. Mystery!

Thank you!


Domenico

John Gallagher ha scritto:
> Doesn't that interrupt fire on both rising and falling edges (i.e. pin 
> change)? That would explain why the ISR executes on release of the 
> button (not why you see two blinks each time though).
>
>
> On Tue, Jan 14, 2014 at 12:46 PM, Domenico Formenton 
> <[email protected] <mailto:[email protected]>> wrote:
>
>     Hi John,
>
>     the code posted is only a test to investigate a problem that has
>     occurred in the real application (without delay, of course). What
>     I see with the LED is also seen with an oscilloscope in a much
>     shorter time, in the millisecond range.
>
>     In actual application, there are other sources of interrupt
>     (serial ports, counters, display) that could obscure the problem.
>
>     I only wanted to reduce to a minimum both the hardware and the
>     software.
>
>     But I have not yet found the solution!
>
>     Thanks anyway for the suggestions.
>     Domenico
>
>     John Gallagher ha scritto:
>>     I am not sure what your problem is, but looking briefly over your
>>     code I wouldn't be surprised if it is due to using delays inside
>>     your ISRs.  This is generally considered a very bad idea, since
>>     it can create all sorts of concurrency / blocking problems. The
>>     way people generally handle a case like yours would be to set a
>>     global flag in the ISR if you want to blink you LED, and then
>>     check the flag and do the actual blinking in your while(1) loop.
>>
>>     This may not be causing your issue, but it also may be. Either
>>     way, it is probably a good idea to make your ISRs as short as
>>     possible, which means removing any delays.
>>
>>
>>     On Tue, Jan 14, 2014 at 11:54 AM, dfx <[email protected]
>>     <mailto:[email protected]>> wrote:
>>
>>         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
>>
>>
>>
>>         ---
>>         Questa e-mail è priva di virus e malware perché è attiva la
>>         protezione avast! Antivirus.
>>         http://www.avast.com
>>
>>         _______________________________________________
>>         AVR-GCC-list mailing list
>>         [email protected] <mailto:[email protected]>
>>         https://lists.nongnu.org/mailman/listinfo/avr-gcc-list
>>
>>
>>
>>
>>     _______________________________________________
>>     AVR-GCC-list mailing list
>>     [email protected]  <mailto:[email protected]>
>>     https://lists.nongnu.org/mailman/listinfo/avr-gcc-list
>
>
>
>     ------------------------------------------------------------------------
>     <http://www.avast.com/> 	
>
>     Questa e-mail è priva di virus e malware perché è attiva la
>     protezione avast! Antivirus <http://www.avast.com/> .
>
>
>



---
Questa e-mail è priva di virus e malware perché è attiva la protezione avast! Antivirus.
http://www.avast.com

_______________________________________________
AVR-GCC-list mailing list
[email protected]
https://lists.nongnu.org/mailman/listinfo/avr-gcc-list

begin:vcard
fn:Domenico Formenton
n:Formenton;Domenico
org:dfx
adr;dom:;;Via delle due Case, 12;APRILIA;LT;04011
email;internet:[email protected]
tel;work:06 92500019
tel;cell:333 7075929
url:www.dfx.it
version:2.1
end:vcard