Ampro Corporation 486E - Manual (Page 77)

Product Reference
2–61
To use the NMI I/O Channel Check in a custom Watchdog Timer handler routine, the standard
NMI handler would have to be replaced with your custom code. If a customer supplied NMI
interrupt service routine is installed, it can test to see if the I/O Channel Check NMI occurred by
reading I/O port 61h, bit 6. Bit 6 is true (1) if the NMI occurred.
Note
Following the occurrence of an I/O Channel Check NMI, the function
must be disabled and then re-enabled before the next one can occur.
The Watchdog timer is not compatible with Windows or other operating systems.