Can’t get AVR pin change interrupt to work

avravr-gccgpio-external-interruptinterrupts

I'm trying to get a pin change interrupt on an Attiny2313 to work but i'm stuck,
the interrupt is not triggering.

I'm using the following code in main():

GIMSK |= (1 << PCIE2);
PCMSK2 |= (1 << PCINT13) | (1 << PCINT14) | (1 << PCINT15);
sei();

This should yield an interrupt on pins PD2, PD3, PD4 i assume?

I have a display attached that shows the bits in PIND (which are indeed changing levels)
And i have defined a uint8_t interruptTriggered = 0; at the top of the file which should get set to 1 in:

ISR(PCINT2_vect) { interruptTriggered = 1; }

I'm also showing the value of interruptTriggered on the display but it never changes to 1.

Note: as the iotn2313.h file included by AtmelStudio 6.1 somehow doesn't include all definitions i took some liberties by defining the following:

//fix some missing definitions for Attiny2313
#define PCMSK2 _SFR_IO8(0x05)
#define PCMSK1 _SFR_IO8(0x04)
#define PCMSK0 _SFR_IO8(0x20)
#define PCINT11 0
#define PCINT12 1
#define PCINT13 2
#define PCINT14 3
#define PCINT15 4
#define PCINT16 5
#define PCINT17 6
#define PCINT1_vect _VECTOR(13)
#define PCINT2_vect _VECTOR(14)
#define PCIE0 5
#define PCIE1 3
#define PCIE2 4

Best Answer

Apparently there is a new revision of ATtiny2313, called ATtiny2313A. This document describes the differences.

The ATtiny2313A is a functionally identical, drop-in replacement for the ATtiny2313. All devices are subject to the same qualification process and same set of production tests, but as the manufacturing process is not the same some electrical characteristics differ.

Amongst other things there are more Pin Change input pins and interrupts as you already noticed.

Ensure that you selected the correct controller type in Atmel Studio, that is including the trailing A in 2313A, and ensure the physical device is an A-version too.

Related Solutions

Electronic – ATtiny45 pin change interrupt PB5

Until I checked the ATtiny45 datasheet today I was convinced that you can't program the AVR after programming RSTDSBL in Fuse High Byte. But then I stumbled over this note under Table 6-7 Start-up Times for Internal Calibrated RC Oscillator Clock"

Note: 1. If the RSTDISBL fuse is programmed, this start-up time will be increased to 14CK + 4 ms to ensure programming mode can be entered.

Now it doesn't mention what programming mode is refered to, either High Voltage or SPI. So if your programmer supports it, you may be able to enter the programming mode within 4ms after power up, instead of using the "\$\overline{\text{RESET}}\$-line protocol" (don't know the proper name for it). You should even be able to verify this without programming the RSTDISBL fuse, and just by programming Start Up Times (SUT[1:0] in Fuse Low Byte) for the internal RC osscillator.

Chapter 20 on page 147 and onwards explains various modes for programming of the devices, but fails to mention the RSTDISBL fuse. Seems you need trial-and-error to be 100% sure ...

I personally use Arduino to ISP program AVR's and I suppose one should be able to hack the ArduinoISP sketch to power up the AVR and start the programming handshake within 4ms after that. But I never tried it myself.

Of course you could reset the fuses for your controller using a high voltage programmer like the AVR Dragon. (Dragon apparently isn't able to power cycle the target device, so Dragon won't support programming without utilizing the \$\overline{\text{RESET}}\$-line). On the other hand, Dragon does support HV programming, which solves your problem either way.

Or you could improvise an HV-programmer to reset the default fuses.

Electronic – avr-gcc timer overflow interrupt handler in inline assembly

I found you post when I was looking for optimization of ISR routine. Finally, I've got a solution which you (and I) wanted to get.

I use Atmel Studio 6.1 (GCC 3.4.2.1002)

ISR(TIM0_OVF_vect,ISR_NAKED)
{
    asm volatile(
        "push   r24"            "\n"
        "in     r24, __SREG__"  "\n"
        "push   r24"            "\n"
        "push   r25"            "\n"

        "lds    r24, %A[_ts]"   "\n"
        "lds    r25, %B[_ts]"   "\n"
        "adiw   r24,1"          "\n"
        "sts    %B[_ts], r25"   "\n"
        "sts    %A[_ts], r24"   "\n"

        "pop    r25"            "\n"
        "pop    r24"            "\n"
        "out    __SREG__,r24"   "\n"
        "pop    r24"            "\n"
        "reti"                  "\n"
        : 
        : [_ts] "m" (ts)
        : "r24", "r25"
    );
}

Here ts is declared as volatile unsigned int ts = 0;
I use named operands ([_ts] "m" (ts)) instead of defailt %0

The result is:


    0000005a <__vector_11>:
    5a: 8f 93           push    r24
    5c: 8f b7           in  r24, 0x3f   ; 63
    5e: 8f 93           push    r24
    60: 9f 93           push    r25
    62: 80 91 60 00     lds r24, 0x0060
    66: 90 91 61 00     lds r25, 0x0061
    6a: 01 96           adiw    r24, 0x01   ; 1
    6c: 90 93 61 00     sts 0x0061, r25
    70: 80 93 60 00     sts 0x0060, r24
    74: 9f 91           pop r25
    76: 8f 91           pop r24
    78: 8f bf           out 0x3f, r24   ; 63
    7a: 8f 91           pop r24
    7c: 18 95           reti

Best Answer

Related Solutions

Electronic – ATtiny45 pin change interrupt PB5

Electronic – avr-gcc timer overflow interrupt handler in inline assembly

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