NEC V850E/RS1 User Manual page 689

(b) Non-maskable interrupt request generated during non-maskable interrupt servicing
Non-maskable
interrupt being
servicing
NMI
INTWDT2
Cautions: 1. NMI signal must not input during NMI servicing. The CPU always accepts the NMI
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Chapter 17 Interrupt/Exception Processing Function
Figure 17-1: Non-Maskable Interrupt Request Acknowledgement Operation (2/2)
Non-maskable interrupt request signal generated during non-maskable interrupt servicing
NMI
• NMI request generated during NMI servicing
NMI
servicing
Main routine
NMI NMI
request request
• NMI request generated during INTWDT2 servicing
INTWDT2
servicing
Main routine
INTWDT2 NMI
request request
pin input, even if NP bit is set.
2. In NMI routine, Software must not operate the PSW: NP_bit. If the NP bit is cleared
by software, the CPU is able to accept the INTWDT2 interrupt and NMI pin input.
User's Manual U16702EE3V2UD00
• INTWDT2 request generated during NMI servicing
(NP = 1 retained before INTWDT2 request)
NMI
servicing
NMI
System reset
request
• INTWDT2 request generated during INTWDT2 servicing
(NP = 1 retained before INTWDT2 request)
NMI
servicing
Main routine
INTWDT2
System reset
request
INTWDT2
NMI
Main routine
servicing
INTWDT2
(Invalid)
request
System reset
INTWDT2
servicing
INTWDT2
(Invalid)
request
System reset
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