HD404849 Datasheet, PDF (22/125 Pages) Hitachi Semiconductor – 4-Bit Single-Chip Microcomputer

Power on
RESET = 0?
No
Yes
Reset MCU
HD404849 Series
Interrupt
request?
No
Yes
No
IE = 1?
Yes
Execute instruction
Accept interrupt
PC ^←(PC) + 1
IE ← 0
Stack ← (PC)
Stack ← (CA)
Stack ^← (ST)
PC^← $0002
PC^← $0004
PC^← $0006
PC^← $0008
PC^← $000A
PC^←$000C
PC^← $000E
Yes
INT₀
interrupt?
No
Yes
INT₁
interrupt?
No
Yes
Timer A
interrupt?
No
Yes _{Timer B/INT2}
interrupt?
No
Yes _{Timer C/INT3}
interrupt?
No
Yes
Timer D
interrupt?
No
(A/D, serial interrupt)
Figure 11 Interrupt Processing Flowchart
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