5 RESET AND NMI
5-4
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
#NMI Pin
5.2.1
The #NMI pin is used to generate a non-maskable interrupt to the C33 PE Core.
To generate an NMI (Non-Maskable Interrupt) to the C33 PE Core, the following two conditions must be met:
(1) A negative edge is detected at the #NMI pin (the #NMI signal changes from a high to a low level).
(2) The #NMI pin is maintained at a low level for three or more system clock cycles.
NMI by the Watchdog Timer
5.2.2
The S1C33L26 has a built-in watchdog timer to detect runaway of the CPU. The watchdog timer outputs a signal if
it is not reset with software (due to CPU runaway) in the programmed cycles. The output signal can generate either
NMI or reset. Write 1 to the NMIEN/WDT_EN register to generate NMI.
For details of the watchdog timer, see the “Watchdog Timer (WDT)” chapter.