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Resets and Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
88
Freescale Semiconductor
5.5.1 Interrupt Recognition and Register Stacking
An interrupt can be recognized at any time after it is enabled by its local mask, if any, and by the global
mask bit in the CCR. Once an interrupt source is recognized, the CPU responds at the completion of the
instruction being executed. Interrupt latency varies according to the number of cycles required to
complete the current instruction. When the CPU begins to service an interrupt, the contents of the CPU
registers are pushed onto the stack in the order shown in
Table 5-5. After the CCR value is stacked, the
I bit and the X bit, if XIRQ is pending, are set to inhibit further interrupts. The interrupt vector for the highest
priority pending source is fetched and execution continues at the address specified by the vector. At the
Table 5-4. Interrupt and Reset Vector Assignments
Vector Address
Interrupt Source
CCR
Mask Bit
Local
Mask
FFC0, C1 – FFD4, D5
Reserved
—
FFD6, D7
SCI serial system
SCI receive data register full
SCI receiver overrun
SCI transmit data register empty
SCI transmit complete
SCI idle line detect
I
RIE
TIE
TCIE
ILIE
FFD8, D9
SPI serial transfer complete
I
SPIE
FFDA, DB
Pulse accumulator input edge
I
PAII
FFDC, DD
Pulse accumulator overflow
I
PAOVI
FFDE, DF
Timer overflow
I
TOI
FFE0, E1
Timer input capture 4/output compare 5
I
I4/O5I
FFE2, E3
Timer output compare 4
I
OC4I
FFE4, E5
Timer output compare 3
I
OC3I
FFE6, E7
Timer output compare 2
I
OC2I
FFE8, E9
Timer output compare 1
I
OC1I
FFEA, EB
Timer input capture 3
I
IC3I
FFEC, ED
Timer input capture 2
I
IC2I
FFEE, EF
Timer input capture 1
I
IC1I
FFF0, F1
Real-time interrupt
I
RTII
FFF2, F3
IRQ (external pin)
I
None
FFF4, F5
XIRQ pin
X
None
FFF6, F7
Software interrupt
None
FFF8, F9
Illegal opcode trap
None
FFFA, FB
COP failure
None
NOCOP
FFFC, FD
Clock monitor fail
None
CME
FFFE, FF
RESET
None