Item1
Item2
SP
TOS
Item1
Item2
SP
TOS
PC
SR
Before
After
PC
SR
Return From Interrupt
Interrupts
53
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
System Resets, Interrupts, and Operating Modes, System Control Module
(SYS)
1.3.4.2
Return From Interrupt
The interrupt handling routine terminates with the instruction:
RETI //return from an interrupt service routine
The return from the interrupt takes five cycles to execute the following actions and is illustrated in
1. The SR with all previous settings pops from the stack. All previous settings of GIE, CPUOFF, and so
on are now in effect, regardless of the settings used during the interrupt service routine.
2. The PC pops from the stack and begins execution where it was interrupted.
Figure 1-4. Return From Interrupt
1.3.5 Interrupt Nesting
Interrupt nesting is enabled if the GIE bit is set inside an interrupt service routine. When interrupt nesting
is enabled, any interrupt occurring during an interrupt service routine interrupts the routine, regardless of
the interrupt priorities.
1.3.6 Interrupt Vectors
The interrupt vectors are located in the address range 0FFFFh to 0FF80h, for a maximum of 64 interrupt
sources. A vector is programmed by the user and points to the start location of the corresponding interrupt
service routine.
is an example of the interrupt vectors available. See the device-specific data
sheet for the complete interrupt vector list.
Table 1-1. Interrupt Sources, Flags, and Vectors
Interrupt Source
Interrupt Flag
System Interrupt
Word Address
Priority
Reset:
power up, external reset
watchdog,
FRAM password
...
WDTIFG
FRCTLPW
...
Reset
...
0FFFEh
...
Highest
System NMI:
JTAG Mailbox
JMBINIFG, JMBOUTIFG
(Non)maskable
0FFFCh
…
User NMI:
NMI
oscillator fault
...
NMIIFG
OFIFG
...
(Non)maskable
(Non)maskable
...
0FFFAh
...
…
Device specific
0FFF8h
…
...
...
...
Watchdog timer
WDTIFG
Maskable
...
...
...
...
...
Device specific
…
…
Reserved
Maskable
…
Lowest