Computer Hardware User's Manual

SubCompact Board GENE-8310
Appendix A Programming the Watchdog Timer A-3
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.
(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.