Fes6905, 1) enter the mb pnp mode, 2) modify the data of the registers – Acnodes FES 6905 User Manual

Page 48: 3) exit the mb pnp mode

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FES6905

Fanless Embedded Controller comes with

Intel Celeron M Processor

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.

(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.