![NEC mPD780065 Series Preliminary User'S Manual Download Page 273](http://html.mh-extra.com/html/nec/mpd780065-series/mpd780065-series_preliminary-users-manual_249264273.webp)
273
CHAPTER 17 INTERRUPT FUNCTIONS
Preliminary User’s Manual U13420EJ2V0UM00
17.4 Interrupt Servicing Operations
17.4.1 Non-maskable interrupt request acknowledge operation
A non-maskable interrupt request is unconditionally acknowledged even if in an interrupt acknowledge disable
state. It does not undergo interrupt priority control and has highest priority over all other interrupts.
If a non-maskable interrupt request is acknowledged, the contents are saved into the stacks in the order of PSW,
then PC, the IE flag and ISP flag are reset (0), and the contents of the vector table are loaded into PC and branched.
A new non-maskable interrupt request generated during execution of a non-maskable interrupt servicing program
is acknowledged after the current execution of the non-maskable interrupt servicing program is terminated (following
RETI instruction execution) and one main routine instruction is executed. However, if a new non-maskable interrupt
request is generated twice or more during non-maskable interrupt servicing program execution, only one non-
maskable interrupt request is acknowledged after termination of the non-maskable interrupt servicing program
execution. Figures 17-7, 17-8, and 17-9 show the flowchart of the non-maskable interrupt request generation through
acknowledge, acknowledge timing of non-maskable interrupt request, and acknowledge operation at multiple non-
maskable interrupt request generation, respectively.
Summary of Contents for mPD780065 Series
Page 2: ...Preliminary User s Manual U13420EJ2V0UM00 2 MEMO ...
Page 10: ...10 Preliminary User s Manual U13420EJ2V0UM00 MEMO ...
Page 22: ...22 Preliminary User s Manual U13420EJ2V0UM00 MEMO ...
Page 134: ...134 Preliminary User s Manual U13420EJ2V0UM00 MEMO ...
Page 154: ...154 Preliminary User s Manual U13420EJ2V0UM00 MEMO ...
Page 160: ...160 Preliminary User s Manual U13420EJ2V0UM00 MEMO ...
Page 186: ...186 Preliminary User s Manual U13420EJ2V0UM00 MEMO ...
Page 326: ...326 Preliminary User s Manual U13420EJ2V0UM00 MEMO ...
Page 342: ...342 Preliminary User s Manual U13420EJ2V0UM00 MEMO ...
Page 350: ...350 Preliminary User s Manual U13420EJ2V0UM00 MEMO ...