Aaeon HSB-800I-A11, Руководство пользователя

Страница: 64 / 75

Appendix A – Watchdog Timer Programming 52
Half
-S
iz
ed
ISA
S
BC
HSB
-800I
-A11
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
results may occur if the MB PnP Mode is not exited normally.
Step 1 – Enter the MB PnP Mode
To enter the MB PnP Mode, four special I/O write operations need 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.
Address Port Data Port
87h, 01h, 55h, 55h: 2Eh 2Fh
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.
Step 3 – Exit the MB PnP Mode
Set bit 1 of the configure control register (Index=02h) to 1 to exit the MB PnP Mode.