Motorola Axiom CMD11E1 Guía de usuario descargar pdf (Pagina 80)

80 CHAPTER 7. INTERRUPT PROCESSING

2. Write the service routine. As part of the service make sure you turn oﬀ the

ﬂag that generated the interrupt.

3. Let HC11 know where to ﬁnd the service. In other words, Link the service

to the request.

With this background, we will modify the square wave generator to use the

interrupt. Here is the complete code with some of the standard equates left out

(you need to have them at the top of the ﬁle!). You should compare this code with

the earlier one. In this code, the main program does nothing really interesting. It

just prints a series of Z’s to the screen

; Various defines go here ...

ORG $3000 don’t forget the $

ME FCC /Your name/

FCB 10

FCC /ECE 372/

FCB 10

FCC /Date the program was last changed/

FCB 10, 10, 4

ORG $2000 DONT FORGET THE $

LDX #ME

JSR OUTSTRG ; MAKE SURE YOU HAVE EQU FOR OUTSTRG

LOOP1

; Enable TOF interrupt by setting TOI (bit#7 in TMSK2)

SEI

LDAA #%10000000

STAA TMSK2

CLI

; Now go about your business of printing Z’s

LDAA #’Z’

LOOP JSR OUTA

BRA LOOP

; End of main program

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Motorola Axiom CMD11E1 Guía de usuario Pagina 80