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CHAPTER 3 CLOCK GENERATOR AND CONTROLLER
[Example]
INT-ENTRY
<Note>
Since the register consists of four bits, the DMA suppression function cannot be used for more
than 15 concurrent interrupts. Always give a DMA task a priority that is at least 15 levels higher
than that of other interrupts.
104
LDI:20
#PDRR, R10
LD
@R10, R1
ADD
#1, R1
ST
R1, @R10
LDI:20
#int-REG, R10
LDI:8
#10H, R1
ST
R1, @R10
:
;
interrupt execute routine
:
LDI:20
#PDRR, R10
LD
@R10, R1
ADD2
#-1, R1
ST
R1, @R10
RETI
; GET PDRR VALUE INTO R1
; PDRR:=PDRR+1, DMA disabled
; int occurred with int-REG
; example, int-flag=#10h
; CLEAR int-REQ, (but still DMA disabled)
; GET PDRR VALUE INTO R1
; PDRR:=PDRR-1, DMA may be enabled
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