MC68HC908GR16A Datasheet, PDF (180/270 Pages) Freescale Semiconductor, Inc – M68HC08 Microcontrollers

System Integration Module (SIM)
15.5.1 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. Figure 15-8 shows
interrupt entry timing. Figure 15-9 shows interrupt recovery timing.
MODULE
INTERRUPT
I BIT
IAB
IDB
R/W
DUMMY
SP
SP – 1 SP – 2 SP – 3 SP – 4 VECT H VECT L START ADDR
DUMMY PC – 1[7:0] PC – 1[15:8] X
A
CCR V DATA H V DATA L OPCODE
Figure 15-8. Interrupt Entry Timing
MODULE
INTERRUPT
I BIT
IAB
IDB
R/W
SP – 4 SP – 3 SP – 2 SP – 1
SP
PC
PC + 1
CCR
A
X PC – 1 [7:0] PC – 1 [15:8] OPCODE OPERAND
Figure 15-9. Interrupt Recovery Timing
MC68HC908GR16A Data Sheet, Rev. 1.0
180
Freescale Semiconductor