Instant Interrupts - Revisited

[Ioannis]

I am trying to make an Interrupt on Rising Edge, PortB.0 on a 16F1827 chip.

When first POR the device, it send the message "Program started" and waits for the Interrupt.

When interrupt happens, Portb.0 is left open (it has pull-up enabled) the ISR is executed sending the message "Hey, I am sleeping!".

And then keeps on sending the message even if the PortB.0 has been restored (grounded).

Anyone sees what stupid thing I missed?

Ioannis

[Darrel Taylor]

Ioannis,

You just need to clear the IOCBF register before exiting the ISR.

IOCBF = 0

[Ioannis]

Oh, I see.

I thought this was taken care by the DT-INTS.

Thanks Darrel,
Ioannis

[Darrel Taylor]

That's what everyone else thinks too, so don't feel too bad.

However, the "Interrupt On Change" on some chips have many interrupt flags that "funnel" into a single IOCIF flag.
DT_INTS only knows about the one IOCIF flag. It has no control over the other 8 flags in the IOCBF register.

It's alot like the USB modules which have 12 interrupt flags that funnel into a single USBIF flag.
But for some reason, nobody expects DT_INTS to handle all of those automatically.
Well actually, if you add DT_HID, they are handled automatically, but that's not the point.

There are too many variations of the IOC interrupts.
Some chips have them on PORTB, some on PORTA, and some have combinatons of PORTA, PORTB and PORTC.
Its the one part of a PIC that you can pretty much assume won't work the same way as the last chip you used.

And there are too many ways you can use IOC interrupts, there's no way I could make something that would work for everybody.
It's much easier for the user to add one or two lines of code to clear the flags the way that best fits the application.

[Ioannis]

Thanks Darrel. Yes I understand that it is too much to ask for your software to cover every variation that Microchip offers.

It was my part to find that, though I got a little confused by the Data sheet and could not see the obvious.

By the way, this little monster (16F1827) has got a core temperature sensor too!

Ioannis

[Ruben Pena]

Hi Darrel: I made a little test with this:
DEFINE OSC 8
' **** CONFIGURACION 16F1826 *************************
#CONFIG
__config _CONFIG1, _FOSC_INTOSC & _MCLRE_OFF & _CP_ON & _WDTE_OFF
__config _CONFIG2, _PLLEN_ON & _LVP_OFF
#ENDCONFIG
ANSELA= %00000001 'Set 'em all to digital
ANSELB= 0 ' 'all digital
ADCON0= 1
adcon1=$80
CM1CON0 = 0
CM2CON0 = 0
OSCCON = $72
'*******************************
LED1 VAR PORTB.3

INCLUDE "DT_INTS-14.bas" ' Base Interrupt System
INCLUDE "ReEnterPBP.bas" ' Include if using PBP interrupts

ASM
INT_LIST macro ; IntSource, Label, Type, ResetFlag?
INT_Handler TMR1_INT, _ToggleLED1, PBP, yes
endm
INT_CREATE ; Creates the interrupt processor
ENDASM

T1CON = $31 ; Prescaler = 8, TMR1ON
@ INT_ENABLE TMR1_INT ; enable Timer 1 interrupts

Main:
PAUSE 1
GOTO Main

'---[TMR1 - interrupt handler]--------------------------------------------------
ToggleLED1:
TOGGLE LED1
@ INT_RETURN

When I compile, I got 2 errors:
574 Illegal opcode (aftersave)
581 Illegal code (AfterUserRoutine)

and two warnings:
574 found label after column 1 (GetAddress)
581 found label after column 1 (GetAddress)
Please help...
Greetings...
Ruben de la Pena V.

[Darrel Taylor]

Ruben,

1) Did you retype the errors, or copy&paste them? The errors are not even the correct format.

2) Have you modified the DT_INTS-14.bas file? The stated errors do not occur when I compile your code.

Try downloading the include files again.
http://www.darreltaylor.com/DT_INTS-14/downloads.htm