mc68hc908gp32 Freescale Semiconductor, Inc, mc68hc908gp32 Datasheet - Page 164

• Manufacturer Part Number: mc68hc908gp32
• Description: M68hc08 Microcontrollers Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

System Integration Module (SIM)
14.5 Exception Control
Normal, sequential program execution can be changed in three different ways:
14.5.1 Interrupts
At the beginning of an interrupt, the CPU saves the CPU register contents on the stack and sets the
interrupt mask (I bit) to prevent additional interrupts. At the end of an interrupt, the RTI instruction recovers
the CPU register contents from the stack so that normal processing can resume.
interrupt entry timing.
Interrupts are latched, and arbitration is performed in the SIM at the start of interrupt processing. The
arbitration result is a constant that the CPU uses to determine which vector to fetch. Once an interrupt is
latched by the SIM, no other interrupt can take precedence, regardless of priority, until the latched
interrupt is serviced (or the I bit is cleared). (See
164
•
•
•
INTERRUPT
I BIT
INTERRUPT
R/W
I BIT
IDB
R/W
IAB
IDB
IAB
MODULE
MODULE
Interrupts:
–
–
Reset
Break interrupts
Maskable hardware CPU interrupts
Non-maskable software interrupt instruction (SWI)
DUMMY
DUMMY
Figure 14-9
SP – 4
SP
PC – 1[7:0]
CCR
Figure 14-9. Interrupt Recovery Timing
Figure 14-8
SP – 3
shows interrupt recovery timing.
SP – 1
MC68HC908GP32 Data Sheet, Rev. 10
PC – 1[15:8]
A
SP – 2
SP – 2
.
Interrupt Entry Timing
X
X
Figure
SP – 1
SP – 3
PC – 1 [15:8] PC – 1 [7:0]
14-10.)
A
SP – 4
SP
CCR
VECT H
PC
OPCODE
V DATA H
PC + 1
VECT L
OPERAND
V DATA L
Figure 14-8
START ADDR
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OPCODE
shows