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S u b C o m p a c t B o a r d
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.
87h, 01h, 55h, 55h:
(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
LDN Index R/W Reset Configuration Register or Action
All
02H
W
07H 71H
R/W 00H
07H 72H
R/W 00H
07H 73H
R/W 00H
07H 74H
R/W 00H
Address Port
2Eh
N/A
Configuration Control
WatchDog Timer Control Register
WatchDog Timer Configuration Register
WatchDog Timer Time-out Value (LSB)
Register
WatchDog Timer Time-out Value (MSB)
Register
Appendix A Programming the Watchdog Timer
G E N E - 5 3 1 5
Data Port
2Fh
A - 3
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