Instant Interrupts - Revisited

[Darrel Taylor]

So far I've shown one interrupt source being used at a time, but as I said in the first post, you can easily service Multiple Interrupt Sources.   So what if we wanted to join the previous 3 examples into one program.   NOT a problem!

To add more interrupt "Handlers", simply add them to the INT_LIST, and create a subroutine for them.

Since both the Blinky Light, and Elapsed Timer used TMR1, lets move the Blinky Light over to TMR0. Elapsed will still use TMR1.

LED1   VAR  PORTD.0
LED2   VAR  PORTD.1

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

ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler    INT_INT,  _ToggleLED1,   PBP,  yes
        INT_Handler   TMR0_INT,  _ToggleLED2,   PBP,  yes
        INT_Handler   TMR1_INT,  _ClockCount,   PBP,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor

    INT_ENABLE   INT_INT     ; enable external (INT) interrupts
    INT_ENABLE  TMR0_INT     ; enable Timer 0 interrupts
    INT_ENABLE  TMR1_INT     ; Enable Timer 1 Interrupts  
ENDASM

OPTION_REG = OPTION_REG & $80 | 1  ; Set TMR0 Prescaler to 256, leave RBPU alone
GOSUB ResetTime              ' Reset Time to  0d-00:00:00.00
GOSUB StartTimer             ' Start the Elapsed Timer

Main:
    IF SecondsChanged = 1 THEN  
       SecondsChanged = 0
       LCDOUT $FE,$C0, DEC Days,"d-",DEC2 Hours,":",DEC2 Minutes,":",DEC2 Seconds
    ENDIF
GOTO Main

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

'---[TMR0 - interrupt handler]-------------------------------(Blinky Light)------
T0Count  VAR WORD
ToggleLED2:
    T0Count = T0Count + 1
    IF T0Count = 512 THEN T0Count = 0 : TOGGLE LED2
@ INT_RETURN

<font size=-2>Code Size = 711 Words</font>

Now we have all three interrupt sources working together in the same program.

LED1 responds to the external INT
LED2 flashes, timed by TMR0
and, the elapsed timer is maintained via TMR1

And, all of this is happening behind the scenes of your normal PBP program.