Aaeon AEC-6811A, Manual

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E m b e d d e d C o n t r o l l e r A E C - 6 8 1 1
Appendix A Programming the Watchdog Timer
A-3
There are three steps to complete the configuration setup: (1) Enter
the MB PnP Mode; (2) Modify the data of configuration registers; (3)
Exit the MB PnP Mode. Undesired result may occur if the MB PnP
Mode is not exited normally.
(1) Enter the MB PnP Mode
To enter the MB PnP Mode, four special I/O write operations are to
be performed during Wait for Key state. To ensure the initial state of
the key-check logic, it is necessary to perform four write opera-tions
to the Special Address port (2EH). Two different enter keys are
provided to select configuration ports (2Eh/2Fh) of the next step.