Program Example Of Interrupt Processing - Fujitsu MB90895 Series Hardware Manual

3.5.19

Program Example of Interrupt Processing

This section gives a program example of interrupt processing.
I Program Example of Interrupt Processing
G
Processing specification
This is an example of interrupt program using external interrupt 4 (INT4).
G
Coding example
DDR2 EQU 000012H
ENIR EQU 030H
EIRR EQU 031H
ELVR EQU 032H
ICR00 EQU 0B0H
STACK SSEG
RW 100
STACK_T RW 1
STACK ENDS
;----------Main program-----------------------------------
CODE CSEG
;
START:
MOV RP,#0
MOV ILM,#07H
MOV A,#!STACK_T
MOV SSB,A
MOVW A,#STACK_T
MOVW SP,A
MOV DDR2,#00000000B
OR CCR,#40H
MOV I:ICR00,#00H
MOV I:ELVR,#00010000B
MOV I:EIRR,#00H
MOV I:ENIR,#10H
:
LOOP NOP
NOP
NOP
NOP
BRA LOOP
;Port 2 direction register
;Interrupt/DTP enable register
;Interrupt/DTP flag
;Request level setting register
;Interrupt control register
;Stack
;Using the head bank as general
purpose register
;Setting ILM in PS to level 7
;Setting of system stack
;Setting of stack pointer
;in this case,S flag=1,so set to SSP
;Setting P24/INT4 pin to input
;I flag of CCR in PS set to interrupt enabled
;Interrupt level 0 (strongest)
;Regard INT4 as H level request
;Clear interrupt factor of INT4
;Input enable of INT4
;Dummy roop
;Jump without condition
CHAPTER 3 CPU
93