External interrupt HW and SW mismatch

Using Arduino Programming Questions
1

Hi,

I was reading the hardware data sheet for the ATMEGA 256, and i identified at least the following external interrupts available:

  • 1 $0000(1) RESET External Pin, Power-on Reset, Brown-out Reset, Watchdog Reset, and JTAG AVR Reset
  • 2 $0002 INT0 External Interrupt Request 0
  • 3 $0004 INT1 External Interrupt Request 1
  • 4 $0006 INT2 External Interrupt Request 2
  • 5 $0008 INT3 External Interrupt Request 3
  • 6 $000A INT4 External Interrupt Request 4
  • 7 $000C INT5 External Interrupt Request 5
  • 8 $000E INT6 External Interrupt Request 6
  • 9 $0010 INT7 External Interrupt Request 7
  • 10 $0012 PCINT0 Pin Change Interrupt Request 0
  • 11 $0014 PCINT1 Pin Change Interrupt Request 1
  • 12 $0016(3) PCINT2 Pin Change Interrupt Request 2

Besides this ones there are others but i didn´t pointed them, because they are irrelevant to my question.

I the reference manual of Arduinos web page comes stated the following:

Specifies a function to call when an external interrupt occurs. Replaces any previous function that was attached to the interrupt. Most Arduino boards have two external interrupts: numbers 0 (on digital pin 2) and 1 (on digital pin 3). The Arduino Mega has an additional four: numbers 2 (pin 21), 3 (pin 20), 4 (pin 19), and 5 (pin 18).

My question is the following, are this external interrupts not supported by the arduino interrupt library?
If not what can i do to take advantage of their existence?

Cheers!

2

Did you look at http://arduino.cc/en/Reference/AttachInterrupt

3

LuisSoares:
I was reading the hardware data sheet for the ATMEGA 256, and i identified at least the following external interrupts available:

  • 8 $000E INT6 External Interrupt Request 6
  • 9 $0010 INT7 External Interrupt Request 7

The Arduino Mega has an additional four: numbers 2 (pin 21), 3 (pin 20), 4 (pin 19), and 5 (pin 18).

Code in arduino core library file WInterrupt.c supports all eight external interrupts for the ATmega1280 and the ATMega2560 chips.

However...

Pins 8 and 9 (INT6 and INT7) are not connected to anything on Arduino Mega1280 or Arduino Mega2560 boards.

Bottom line: Arduino software supports them but "official" Arduino hardware does not. Make your own PC board with the '1280 or ''2560 and you can use all of them. (If someone has anything like that for sale, I'm guessing they just might tell us about them here.)

Regards,

Dave

4

Pins 8 and 9 (INT6 and INT7) are not connected to anything on Arduino Mega1280 or Arduino Mega2560 boards.

The Seeeduino Mega board (1280 based) does bring all I/O pins out to connector pads including chip pins 8 and 8. However I'm not sure the arduino core pin mapping includes these pins along with 14 other 'missing' pins, probably not. I don't think I will ever understand why arduino did not wire up the additional 16 I/O pins that the 1280/2560 offers?

Lefty

5

retrolefty:
I don't think I will ever understand why arduino did not wire up the additional 16 I/O pins that the 1280/2560 offers?

+1