Advantech PCM-9574, Руководство пользователя

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Chapter 2 Installation 19
2.11 Keyboard and PS/2 mouse connector (CN5)
The PCM-9574 board provides a keyboard connector that supports
both a keyboard and a PS/2 style mouse. In most cases, especially in
embedded applications, a keyboard is not used. The standard PC/AT
BIOS will report an error or fail during power-on self-test (POST)
after a reset if the keyboard is not present. The PCM-9574’s BIOS
standard setup menu allows you to select “All, But Keyboard” under
the “Halt On” selection. This allows no-keyboard operation in
embedded system applications without the system halting under
POST (power-on-self-test).
2.12 Front panel connector (CN18)
Next, you may want to install external switches to monitor and control
the PCM-9574. These features are optional - install them only if you
need them. The front panel connector (CN18) is an 8-pin male, dual
in-line header and provides connections for a speaker, hard disk
access indicator, watchdog output and an input switch for resetting
the card.
2.12.1 Speaker
The PCM-9574 can drive an 8
Ω
speaker at 0.5 watts. Make sure that
alternatives to this specification do not overload the card.
2.12.2 LED interface
The front panel LED indicator for hard disk access is an active low
signal (24 mA sink rate).
2.12.3 Watchdog output
When PCM-9574 watchdog timer times out, the front panel pin 6 will
output an active low pulse signal (25 mA sink rate for 1 second).