235
8.7 Hold Request Cancel Request
8.7
Hold Request Cancel Request
For processing a high-priority interrupt while the CPU is in hold state, cancellation of
the hold request must be requested from the source for the hold request. The interrupt
level used to determine whether to issue a cancel request must be set in the HRCL
register.
■
Criteria for Determining Whether to Issue a Hold Request Cancel Request
When an interrupt cause having a higher level than that set in the HRCL register is generated, a
hold request cancel request is issued.
A cancel request remains valid and DMA transfer remains suppressed unless the interrupt
cause triggering the cancel request is cleared. To prevent this problem, clear the corresponding
interrupt cause.
■
Interrupt Levels for which a Hold Request Cancel Request is Available
The values that can be set in the HRCL register range from 10000
B
to 11111
B
, as with the ICR
register.
When 11111
B
is set, a cancel request is issued for every interrupt level. When 10000
B
is set, a
cancel request is issued only for NMI.
Table 8.7-1 lists the settings for the interrupt levels for which a hold request cancel request is
issued.
After the HRCL register is reset, hold requests for all interrupt levels are canceled.
In this situation, DMA transfer is not performed if interrupts occur, and so set the HRCL register
value should be set to the appropriate value.
Interrupt level set in the HRCL register
@
Interrupt level after priority check
A cancel request is issued
Interrupt level set in the HRCL register
@
Interrupt level after priority check
No cancel request is issued
Table 8.7-1 Settings for the Interrupt Levels for which a Hold Request Cancel Request is
Issued
HRCL register
Interrupt levels for which a hold request cancel request is issued
16
NMI only
17
NMI and interrupt level 16
18
NMI, and interrupt levels 16 and 17
31
NMI, and interrupt levels 16 to 30 (initial value)
Summary of Contents for MB91F109
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Page 10: ...vi ...
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Page 96: ...72 CHAPTER 2 CPU ...
Page 224: ...200 CHAPTER 4 BUS INTERFACE ...
Page 234: ...210 CHAPTER 5 I O PORTS ...
Page 268: ...244 CHAPTER 9 U TIMER ...
Page 290: ...266 CHAPTER 10 UART ...
Page 314: ...290 CHAPTER 12 16 BIT RELOAD TIMER ...
Page 322: ...298 CHAPTER 13 BIT SEARCH MODULE ...
Page 392: ...368 CHAPTER 16 FLASH MEMORY ...
Page 432: ...408 APPENDIX E Instructions F Table E 2 Instruction Formats OP rel11 5 11 ...
Page 448: ...424 APPENDIX E Instructions ...
Page 449: ...425 INDEX INDEX The index follows on the next page This is listed in alphabetic order ...
Page 458: ...434 INDEX ...
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Page 461: ...FUJITSU SEMICONDUCTOR FR30 32 Bit Microcontroller MB91F109 Hardware Manual ...