CHAPTER 12 DMA FUNCTIONS
User’s Manual U13850EJ6V0UD
464
Figure 12-8. When Interrupt Servicing Occurs Twice During DMA Operation (1/2)
(a) Normal interrupt servicing
RETI
EI
Interrupt request
Main routine
Interrupt servicing routine
Interrupt request flag (xxIFn) is
cleared (0).
(b) Interrupt servicing when interrupt servicing occurs twice
EI
RETI
RETI
Interrupt request flag (xxIFn) is
cleared (0).
Main routine
Interrupt servicing routine
Interrupt request flag (xxIFn) is
not cleared and remains 1.
Bit manipulation
instruction to xxIFn
Interrupt request
Since the interrupt request flag
(xxIFn) remains 1, the interrupt
is serviced again.
Remark
xx: Identification name of each peripheral unit (see
Table 5-2
)
n: Peripheral unit number (see
Table 5-2
)