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CHAPTER 12 INTERRUPT CONTROLLER
12.6 Hold-Request Cancellation Request
To handle an interrupt with a higher priority while the CPU is in hold status, the
requester of the hold request must cancel that request. The interrupt level used to
determine whether a hold-request cancellation request is issued needs to be set in the
HRCL register.
■
Criteria for determining whether a hold-request cancellation-request must be issued
If an interrupt source with an interrupt level higher than that specified in the HRCL register is
issued, a hold-request cancellation request must be generated.
•
Interrupt level of HRCL register is greater than Interrupt level after evaluating priority
--> Cancellation request issued
•
Interrupt level of HRCL register is equal to or less than Interrupt level after evaluating priority
--> Cancellation request not issued
Since this cancellation request is valid unless the interrupt source is cleared, DMA transfer does
never start. Be sure to clear the corresponding interrupt source.
■
Levels that can be set for hold request cancellation requests
A number from 0000
B
to 1111
B
can be set in the HRCL register.
When 1111
B
is set, the cancellation request is issued for all interrupt levels. When 0000
B
is set,
the cancellation request is issued only for NMI.
Table 12.6-1 "Interrupt levels for which the hold-request cancellation request is issued" lists the
interrupt levels for which the hold-request cancellation request is issued.
Note:
After a reset, DMA transfer is disabled for all interrupt levels. This means that DMA transfer
is not performed when an interrupt has been issued. Therefore, set the HRCL register to the
appropriate value.
Table 12.6-1 Interrupt levels for which the hold-request cancellation request is issued
HRCL register
Interrupt levels for which the hold-request cancellation
request is issued
16
(Only NMI)
17
Interrupt level 16
18
Interrupt levels 16 to17
:
:
31
Interrupt levels 16-30 [initial value]
Содержание MB91150 Series
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Страница 3: ...FUJITSU LIMITED FR30 32 BIT MICROCONTROLLER MB91150 Series HARDWARE MANUAL ...
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Страница 112: ...96 CHAPTER 3 MEMORY SPACE CPU AND CONTROL UNIT ...
Страница 174: ...158 CHAPTER 5 I O PORTS Note DDRI bit 6 is a test bit Always set the bit to 0 The value read from this bit is always 0 ...
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Страница 214: ...198 CHAPTER 7 16 BIT RELOAD TIMER ...
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Страница 310: ...294 CHAPTER 13 8 10 BIT A D CONVERTER ...
Страница 318: ...302 CHAPTER 14 8 BIT D A CONVERTER ...
Страница 362: ...346 CHAPTER 15 UART ...
Страница 420: ...404 CHAPTER 19 PERIPHERAL STOP CONTROL ...
Страница 428: ...412 CHAPTER 20 CALENDAR MACROS ...
Страница 503: ...487 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
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