Aaeon AEC-6637, User Manual

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Appendix A – Watchdog Timer Programming 98
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(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 operations to the Special Address port (2EH). Two
different enter keys are provided to select configuration ports (2Eh/2Fh) of the next
step.
(2) Modify the Data of the Registers
All configuration registers can be accessed after entering the MB PnP Mode. Before
accessing a selected register, the content of Index 07h must be changed to the LDN to
which the register belongs, except some Global registers.
(3) Exit the MB PnP Mode
Set bit 1 of the configure control register (Index=02h) to 1 to exit the MB PnP Mode.
WatchDog Timer Configuration Registers
Configure Control (Index=02h)
This register is write only. Its values are not sticky; that is to say, a hardware reset will
automatically clear the bits, and does not require the software to clear them.