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MB90620 series
CHAPTER 15 Delayed Interrupt Generator Module
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15.2 Operation of the Delayed Interrupt Generator Module
When software causes the CPU to write “1” to the relevant bit of DIRR, the request
latch in the delayed interrupt generator module is set and an interrupt request is
generated to the interrupt controller.
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Operation of the Delayed Interrupt Generator Module
When software causes the CPU to write “1” to the relevant bit of DIRR, the request latch in the
delayed interrupt generator module is set and an interrupt request is generated to the interrupt
controller. If the priority of other interrupt requests is lower than that of this interrupt or no other
interrupt request is generated, the interrupt controller generates an interrupt request to the
F2MC-16LX CPU. The F2MC-16LX CPU compares the ILM bit of the internal CCR register and
the interrupt request. When the request level is higher than that of the ILM bit, the CPU starts the
hardware interrupt processing microprogram immediately after execution of the current
instruction ends. As a result, the interrupt processing routine for this interrupt is executed. This
interrupt cause is cleared and task switching is done by writing “0” to the relevant bit of DIRR in
the interrupt processing routine. Figure 15.2-1 shows the operation of the delayed interrupt
generator module.
Figure 15.2-1 Operation of the delayed interrupt generator module
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Note on using the delayed interrupt generator module
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Delayed interrupt request latch
This latch is set by writing “1” to the relevant bit of DIRR and cleared by writing “0” to the same
bit. Note that interrupt processing is restarted the moment control returns from interrupt
processing unless software is created to clear the cause in the interrupt processing routine.
F MC-16LX CPU
Delayed interrupt generator module
Delayed interrupt controller
WRITE
Other
request
DDIR
ICR vv
CMP
ICR xx
ICR vv
CMP
NTA
ICR xx