UPD784044 Datasheet, PDF (40/90 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLER

µPD784044(A), 784046(A)
8. INTERRUPT FUNCTION
The three types of interrupt processing shown in Table 8-1 can be selected.
Table 8-1. Interrupt Request Processing
Processing Mode
Vectored interrupt
Context switching
Macro service
Processed by:
Software
Firmware
Processing
Branches to and executes processing routine
(any processing contents).
Automatically selects register bank, and branches
to and executes processing routine (any
processing contents).
Executes data transfer between memory and I/O
(any processing contents).
Contents of PC and PSW
Saves and restores to/from
stack.
Saves or restores to/from
fixed area in register bank.
Retained
8.1 Interrupt Source
As interrupt sources, twenty-seven sources listed in Table 8-2, BRK instruction execution, and operand error
are available.
Four priority levels of interrupt processing can be selected, so that nesting during interrupt processing and
the levels of interrupt requests that are generated at the same time can be controlled. However, nesting always
advances with macro service (i.e., nesting is not kept pending).
The default priority is the priority (fixed) of the processing for the interrupt requests that have occurred at
the same time and have the same priority level (refer to Table 8-2).
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