18F4550, How to use multiple External Interupts

[wdmagic]

Ok someone else just posted an article with INT's and a response looks very good, first look at my original post code, this works for one interupt, now heres the code that made me interested (if this is part of darrels routines let me know)

INTCON2.6 = 0   'Interrupt on falling edge of INT0
INTCON2.5 = 1   'Interrupt on rising edge of INT1

' Here two interrupts are declared. One for INT0 (PortB.0) and one for INT1 (PortB.1). 

ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler    INT0_INT,  _RcvCAN,   PBP,  yes
        INT_Handler    INT1_INT,  _DoSomething, PBP, yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM

Main:
  Pause 100
  Toggle LED
Goto Main

RcvCAN:
' Put your code here or GOSUB it but make SURE you have a RETURN at the end of the routine so you come back here, otherwise you'll crash.
@ INT_RETURN

DoSomethingElse:
Toggle AnotherLED
@ INT_RETURN

now if this is darrels way then I can see the ease of use, im not sure why INT0 and INT1 have falling and leading edge differnt but thats ok. I would like to know how to alter my original code to use 3 interupts though?

[HenrikOlsson]

Hi,
Yes, this is an example of how to use DT-INTS, if you want more information on it I strongly suggest that you
A) Check Darrels website and all his examples and
B) Search the forum because there's been a TON of examples and discussions on these great routines over the years.

im not sure why INT0 and INT1 have falling and leading edge differnt but thats ok

That was just to show that you CAN select on which edge the interrupt should fire. You want them both (or all three including INT2) on the falling edge then you set them up that way.

I would like to know how to alter my original code to use 3 interupts though?

Using ON INTERRUPT:
First you set up the three interrupts you want to use and enable them, just like you've done with INT0 in your working example. To determine which of the three interrupts that fired you check the three individual interrupt flags in your interrupt service routine and act accordingly. Before you leave the interrupt service routine you clear the interrupt flag that caused the interrupt. (I thought we covered that earlier in the thread).

/Henrik.