Signal
Definition
Speaker
The signal on the Speaker pin is referenced to +5V out. Connect a speaker between this pin
and +5V out.
PW LED
Switched power output to connect a panel power LED. No series resistor is needed.
ATX power button The ATX power button should be tied to ground whenever the “Power Button” is used. The
“Power Button” has different functionality, depending on the current system mode and
software operation. In general, the following guidelines apply.
•
If the board is powered down, toggling (i.e., tie to ground briefly, then release) this
button turns the system on, causing all non-standby voltages to become active.
NOTE: depending on the default configuration, the system usually powers-up
immediately as power is applied.
•
If the system is currently powered up and active, toggling (i.e., tie to ground briefly, then
release) this button causes a system power-down event to be initiated. Typically, this
powers-down the monitor, hard drive, and any other non-essential functions. The system
must be operating and the software executing normally for this function. Under
Windows and some other OSs, this power-down event may cause the system to shut
down. Typically, this is software-configurable via an option setting for the given OS.
•
If the system is currently powered-up and active, holding this button for four seconds
causes a forced system shutdown. This is a hardware power-down, which can be
detrimental to many OSs due to the fact that they are not given adequate time to initiate
shut-down sequencing. This operation should only be used in critical circumstances,
such as when the system itself is locked due to system instability or a software crash.
After powering the system down in this manner, the system remains powered down until
the power button is toggled (tied to ground again and released).
When ATX is enabled, a momentary contact between this pin and Ground causes the CPU to
turn on and a contact of four seconds or longer generates a power shutdown.
ATX power control is enabled using a jumper on jumper block JP7.
Ground
Ground
Reset key
Connection between Reset key and ground generate a reset condition. The board remains in a
reset state (with non-standby power rails disabled) until Reset key is removed from ground.
Diamond Systems Corporation
Poseidon User Manual
Page 18