APPENDIX
Appendix 8. 7906 Group Q & A
Interrupts
A
To prevent this problem, make sure that the routine which should not accept a certain interrupt
request will be executed after the change of the interrupt priority level (IPL) has been completed.
(This is to be made by software.)
The following is a sample program.
[Sample program]
After writing “0002” to the interrupt priority level select bits, the instruction queue buffer is filled with
several NOP instructions to make the next instruction not to be executed before this writing is
completed.
:
MOVMB XXXIC, #00H
NOP
:
; Writes “0002” to the interrupt priority level select bits.
; Inserts ten NOP instructions.
NOP
;
LDA
:
A,DATA
; Instruction at the beginning of the routine that should not accept a
certain interrupt request
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7906 Group User’s Manual Rev.2.0
20-105
RENESAS [ RENESAS TECHNOLOGY CORP ]
