Aaeon PCM-QM77 Manual de usuario descargar pdf (Pagina 133)

Compact Board PCM-QM77

Appendix A Programming the Watchdog Timer A-3

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

Write exit key 0xAA to the index port.

1 2 ... 128 129 130 131 132 133 134 135 136 137 138 ... 171 172

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Aaeon PCM-QM77 Manual de usuario Pagina 133