Chapter 15 Interrupt Controller
15-6
15.3.4 Interrupt priority assigning
When multiple interrupt requests exist, the Interrupt Controller selects the interrupt with the highest
priority according to the priority level and interrupt number. Interrupt factors with an interrupt level
equal to or lower than the interrupt level specified by the Interrupt Mask Level Register (IRMSK) will
be excluded (masked).
When the interrupt with the highest priority is selected, then the interrupt number of that interrupt is
set in the interrupt factor field (CAUSE) of the Interrupt Current Status Register (IRCS), the interrupt
level is set in the Interrupt Level field (LVL), and the Interrupt Flag bit (IF) is set.
Priorities are assigned as follows.
•
When interrupt levels differ, the interrupt with the higher interrupt level has priority (Table
15.3.2)
•
When multiple interrupts with the same interrupt level are simultaneously detected, the
interrupt with the smaller interrupt number has priority (Table 15.3.1).
In the following cases, interrupts are reprioritized. If any new interrupt requests are generated before
reprioritization, the highest-priority interrupt is accepted, changing the Interrupt Cause (CAUSE) and
Interrupt Level (LVL) fields in the Interrupt Current Status (IRCS) register.
•
When an interrupt request with a higher interrupt level than that of the currently selected
interrupt is detected. If the interrupt levels are equal, the Interrupt Cause (CAUSE) field does
not change, even if the interrupt number is smaller.
•
When the interrupt level (IRLVLn.ILm) of the currently selected interrupt changes to a value
smaller than the current setting.
•
When the currently selected interrupt is cleared (refer to 15.3.6 Clearing interrupt requests).
Changing the Interrupt Mask Level (IRMSK.LML) does not cause the IRC to reprioritize interrupts.
However, if the Interrupt Mask Level (IRMSK.LML) is set to a value equal to or greater than the
current interrupt level (IRLVLn.ILm), the Interrupt Flag bit in the Interrupt Current Status register
(IRCS.IF) is set to mask the interrupt.
Summary of Contents for TX49 TMPR4937
Page 1: ...64 Bit TX System RISC TX49 Family TMPR4937 Rev 2 0 ...
Page 4: ......
Page 13: ...Table of Contents ix TMPR4937 Revision History 1 ...
Page 14: ...Table of Contents x ...
Page 15: ...Handling Precautions ...
Page 16: ......
Page 18: ...1 Using Toshiba Semiconductors Safely 1 2 ...
Page 40: ...3 General Safety Precautions and Usage Considerations 3 18 ...
Page 42: ...4 Precautions and Usage Considerations 4 2 ...
Page 43: ...TMPR4937 2005 3 Rev 2 0 ...
Page 44: ......
Page 52: ...Chapter 1 Overview and Features 1 6 ...
Page 156: ...Chapter 7 External Bus Controller 7 56 ...
Page 491: ...Chapter 16 Removed 16 1 16 Removed ...
Page 492: ...Chapter 16 Removed 16 2 ...
Page 493: ...Chapter 17 Removed 17 1 17 Removed ...
Page 494: ...Chapter 17 Removed 17 2 ...
Page 495: ...Chapter 18 Removed 18 1 18 Removed ...
Page 496: ...Chapter 18 Removed 18 2 ...
Page 497: ...Chapter 19 Removed 19 1 19 Removed ...
Page 498: ...Chapter 19 Removed 19 2 ...
Page 506: ...Chapter 20 Extended EJTAG Interface 20 8 ...
Page 530: ...Chapter 22 Pinout and Package Information 22 10 ...
Page 542: ...Chapter 24 Parts Number when Ordering 24 2 ...