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CHAPTER 17 DTP/EXTERNAL INTERRUPTS
17.6 Program Example of DTP/External Interrupt Function
This section gives a program example of the DTP/external interrupt function.
■ Program Example of DTP/External Interrupt Function
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Processing specifications
An external interrupt is generated by detecting the rising edge of the pulse input to the INT8 pin.
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Coding example
ICR07 EQU 0000B7H ;Interrupt control register ICR7
DDR5 EQU 000015H ;Port 5 direction register
ENIR1 EQU 0000CAH ;DTP/external interrupt enable
register 1
EIRR1 EQU 0000CBH ;DTP/external interrupt factor
register 1
ELVR1L EQU 0000CCH ;Detection level setting register 1:"L"
ELVR1H EQU 0000CDH ;Detection level setting register 1:"H"
ADER5 EQU 00000BH ;Port5 analog input enable register
ER8 EQU EIRR1:0 ;INT8 Interrupt request flag bit
EN8 EQU ENIR1:0 ;INT8 Interrupt request enable bit
;---------Main program-------------------------------------
CODE CSEG
START: ;Stack pointer (SP) already initialized
MOV I:ADER5,#00000000B ;Set analog input of Port5 to disable
MOV I:DDR5,#00000000B ;Set DDR5 to input port
AND CCR,#0BFH ;Interrupts disabled
MOV I:ICR07,#00H ;Interrupt level 0 (highest)
CLRB I:EN8 ;INT8 disabled using ENIR1
MOV I:ELVR0L,#00000010B;Rising edge selected for INT8
CLRB I:ER0 ;INT8 interrupt flag cleared using
;EIRR1
SETB I:EN8 ;INT8 interrupt request enabled using
ENIR1
MOV ILM,#07H ;Set ILM in PS to level 7
OR CCR,#40H ;Interrupts enabled
LOOP:
ÅE
Processing by user
ÅE
BRA LOOP
;---------Interrupt program-------------------------------------
WARI:
CLRB I:ER8 ;Interrupt request flag cleared