Aaeon AEC-6821, Manual

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E m b e d d e d C o n t r o l l e r A E C - 6 8 2 1
Appendix A Programming the Watchdog Timer
A-12
(3) Exit the W83627EHG config Mode. Undesired result may
occur if the config Mode is not exited normally.
(1) Enter the W83627EHG config Mode
To enter the W83627EHG 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 W83627EHG config Mode
The exit key is provided to select configuration ports (2Eh/2Fh) of
the next step.
Address Port Data Port
0aah: 2Eh 2Fh
WatchDog Timer Register I (Index=F5h, Default=00h)
CRF5 (PLED mode register. Default 0 x 00)
Bit 7-6 : select PLED mode
= 00 Power LED pin is tri-stated.
= 01 Power LED pin is drived low.