NMI
Nonmaskable Interrupt
7-124
Syntax
NMI
Operands
None
Opcode
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
0
1
0
0
1
0
1
0
0
1
1
1
1
1
0
1
Execution
(PC) + 1
→
stack
24h
→
PC
1
→
INTM
Status Bits
Affects
INTM
This instruction is not affected by INTM.
Description
The NMI instruction forces the program counter to the nonmaskable interrupt
vector located at 24h. This instruction has the same effect as the hardware
nonmaskable interrupt NMI.
Words
1
Cycles for a Single NMI Instruction
ROM
DARAM
SARAM
External
4
4
4
4+3p
†
† The ’C2xx performs speculative fetching by reading two additional instruction words. If the PC
discontinuity is taken, these two instruction words are discarded.
Example
NMI
;PC + 1 is pushed onto the stack, and then
;control is passed to program memory location
;24h.
Cycles