MC68HC05SU3A Datasheet, PDF (36/80 Pages) Freescale Semiconductor, Inc – Fully static chip design featuring the industry standard 8-bit M68HC05 core

Freescale Semiconductor, Inc.
From RESET
Y
Is I-bit Set?
N
IRQ External
Y
Interrupt ?
Clear
External Interrupt
Request Latch
5
N
IRQ2 External
Y
Interrupt ?
N
Timer Interrupt?
Y
PC → (SP, SP–1)
X → (SP–2)
A → (SP–3)
CC→ (SP–4)
N
Keyboard Interrupt? ^Y
Set I-bit in CCR
N
Load Interrupt
Vectors to
Program Counter
Fetch Next
Instruction
Y
SWI Instruction?
N
Y
RTI Instruction?
N
Execute
Instruction
Restore Registers
from Stack
CC, A, X, PC
Figure 5-2 Hardware Interrupt Processing Flowchart
TPG
RESETS AND INTERRUPTS
MC68HC05SU3A
5-4
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