Rev. 1.0, 09/01, page 102 of 904
5.7
Usage Notes
5.7.1
Contention between Interrupt Generation and Disabling
When an interrupt enable bit is cleared to 0 to mask interrupts, the masking becomes effective
after execution of the instruction.
When an interrupt enable bit is cleared to 0 by an instruction such as BCLR or MOV, if an
interrupt is generated during execution of the instruction, the interrupt concerned will still be
enabled on completion of the instruction, and so interrupt exception handling for that interrupt will
be executed on completion of the instruction. However, if there is an interrupt request of higher
priority than that interrupt, interrupt exception handling will be executed for the higher-priority
interrupt, and the lower-priority interrupt will be ignored. The same also applies when an interrupt
source flag is cleared to 0. Figure 5.6 shows an example in which the TCIEV bit in the TPU’s
TIER_0 register is cleared to 0. The above contention will not occur if an enable bit or interrupt
source flag is cleared to 0 while the interrupt is masked.
Internal
address bus
Internal
write signal
φ
TCIEV
TCFV
TCIV
interrupt signal
TIER_0 write cycle by CPU
TCIV exception handling
TIER_0 address
Figure 5.6 Contention between Interrupt Generation and Disabling
Содержание H8S/2376 F-ZTAT
Страница 24: ...Rev 1 0 09 01 page xxiv of xliv ...
Страница 38: ...Rev 1 0 09 01 page xxxviii of xliv ...
Страница 44: ...Rev 1 0 09 01 page xliv of xliv ...
Страница 60: ...Rev 1 0 09 01 page 16 of 904 ...
Страница 96: ...Rev 1 0 09 01 page 52 of 904 ...
Страница 116: ...Rev 1 0 09 01 page 72 of 904 ...
Страница 148: ...Rev 1 0 09 01 page 104 of 904 ...
Страница 284: ...Rev 1 0 09 01 page 240 of 904 ...
Страница 422: ...Rev 1 0 09 01 page 378 of 904 ...
Страница 634: ...Rev 1 0 09 01 page 590 of 904 ...
Страница 656: ...Rev 1 0 09 01 page 612 of 904 ...
Страница 668: ...Rev 1 0 09 01 page 624 of 904 ...
Страница 780: ...Rev 1 0 09 01 page 736 of 904 ...
Страница 796: ...Rev 1 0 09 01 page 752 of 904 ...
Страница 806: ...Rev 1 0 09 01 page 762 of 903 ...
Страница 808: ...Rev 1 0 09 01 page 764 of 904 ...
Страница 921: ...Rev 1 0 09 01 page 877 of 904 ø tBRQOD tBRQOD Figure 24 24 External Bus Request Output Timing ...
Страница 938: ...Rev 1 0 09 01 page 894 of 904 ...