Aaeon HSB-835A, User Manual

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H a l f - s i z e C P U C a r d H S B - 8 3 5 A
Appendix B Programming the Watchdog Timer
B-3
There are three steps to complete the configuration setup:
(1) Enter the W83627HF config Mode
(2) Modify the data of configuration registers
(3) Exit the W83627HF config Mode. Undesired result may
occur if the config Mode is not exited normally.
(1) Enter the W83627HF config Mode
To enter the W83627HF config Mode, two 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 two write operations to the Special Address port
(2EH). The different enter keys are provided to select
configuration ports (2Eh/2Fh) of the next step.
Address Port Data Port
87h,87h: 2Eh 2Fh
(2) Modify the Data of the Registers
All configuration registers can be accessed after entering the
config 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 W83627HF config Mode
The exit key is provided to select configuration ports
(2Eh/2Fh) of the next step.