Fujitsu FR20 Manual De Usuario
233
15.3
Operation of Interrupt Controller
The interrupt request generated at the resource is controlled by the interrupt-enabled
bit that has been set per resource. If an interrupt is enabled at each resource, the
generated interrupt request generates an interrupt request signal to the interrupt
controller.
bit that has been set per resource. If an interrupt is enabled at each resource, the
generated interrupt request generates an interrupt request signal to the interrupt
controller.
■
Priority Order Evaluation
The interrupt controller selects the highest priority factor from those that have been generated
simultaneously, and outputs the factor's interrupt level and interrupt number to the CPU.
The criteria for evaluating the priority order of the interrupt causes are shown below.
●
The interrupt cause meets the following conditions:
•
The interrupt cause has an interrupt level other than 31 (A value of 31 represents interrupt disable.)
•
The interrupt cause has the lowest interrupt level
•
The interrupt cause has the smallest interrupt number
Table 15.3-1 shows the relationship between interrupt causes, interrupt numbers, and interrupt levels.
Figure 15.3-1 Flowchart of interrupt cause
Interrupt Controler
CPU
Resource request 01
ICR01
Resource request 02
ICR02
CMP
IL
Resource request xx
ICRxx
CMP
ILM
Resource request yy
ICRyy