18F1220 and DT Instant Interrupts

[jderson]

I was successful in getting the "Hello World" program to work, but not so lucky with the "Blinky Light" program. The code below causes PORTB.4 to:

1. Go high on power-up for approximately 1 second.
2. Go low for a VERY short period of time.
3. Go high and stay there.

Observations made w/O.Scope

TRISA = %00100000
TRISB = %00000111
WDTCON = 0
ADCON0 = %00000000
ADCON1 = %01111111
LVDCON = %00000000
CCP1CON = %00000000
OSCCON = %01100010
RCON = %10000010
EECON1 = %00000100
INTCON2 = %11000000
INTCON3 = %01011011
PIE2 = %00000000
IPR2 = %00000000
RCON = %10000000
T2CON = %00000000
T3CON = %00000000
TXSTA = %00000000
RCSTA = %00000000

@ __CONFIG _CONFIG1H, _IESO_OFF_1H & _FSCM_OFF_1H & _INTIO2_OSC_1H
@ __CONFIG _CONFIG2L, _PWRT_ON_2L & _BOR_OFF_2L & _BORV_27_2L
@ __CONFIG _CONFIG2H, _WDT_OFF_2H & _WDTPS_32K_2H
@ __CONFIG _CONFIG3H, _MCLRE_OFF_3H
@ __CONFIG _CONFIG4L, _DEBUG_OFF_4L & _LVP_OFF_4L & _STVR_OFF_4L
@ __CONFIG _CONFIG5L, _CP0_OFF_5L & _CP1_OFF_5L
@ __CONFIG _CONFIG5H, _CPB_OFF_5H & _CPD_OFF_5H
@ __CONFIG _CONFIG6L, _WRT0_OFF_6L & _WRT1_OFF_6L
@ __CONFIG _CONFIG6H, _WRTC_OFF_6H & _WRTB_OFF_6H & _WRTD_OFF_6H
@ __CONFIG _CONFIG7L, _EBTR0_OFF_7L & _EBTR1_OFF_7L
@ __CONFIG _CONFIG7H, _EBTRB_OFF_7H

LED1 VAR PORTB.4

INCLUDE "DT_INTS-18.bas" ' Base Interrupt System
INCLUDE "ReEnterPBP-18.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

Why doesn't it blink?

Thank you for any help.

[Darrel Taylor]

It could be the ...

INTCON3 = %01011011

Which enables both INT1 and INT2, and SET's their Interrupt flags.

But since there aren't any handlers for those interrupts, the IF bit never gets reset, and the system locks up on Un-Handled interrupts.

hth,

ADDED: DT_INTS handles ALL the enable, priority and interrupt flag bits. There's no need to set them manually.

[jderson]

That solved the problem! Thank you Darrell, and thank you for the use of your programs.

[Darrel Taylor]

My Pleasure!

Wait till you've got 6 or 7 different interrupts firing.
You'll love it even more. :)
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