System Integration Module (SIM)
Exception Control
MC68HC908GP32
•
MC68HC08GP32
—
Rev. 6
Technical Data
MOTOROLA
System Integration Module (SIM)
289
processing can resume.
Figure 19-8
shows interrupt entry timing.
Figure 19-9
shows interrupt recovery 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
Figure
19-10
.)
Figure 19-8
.
Interrupt Entry Timing
Figure 19-9. Interrupt Recovery Timing
MODULE
IDB
R/W
INTERRUPT
DUMMY
SP
SP – 1
SP – 2
SP – 3
SP – 4
VECT H
VECT L
START ADDR
IAB
DUMMY
PC – 1[7:0] PC – 1[15:8]
X
A
CCR
V DATA H
V DATA L
OPCODE
I BIT
MODULE
IDB
R/W
INTERRUPT
SP – 4
SP – 3
SP – 2
SP – 1
SP
PC
PC + 1
IAB
CCR
A
X
PC – 1 [15:8] PC – 1 [7:0]
OPCODE
OPERAND
I BIT
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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