Signal
Definition
+5V in
+5V main input power.
Ground
0-V (ground) power return path.
+12V in
Power supply for in-board 12V devices, including hard drives, auxiliary
power, PC/104 power, and LCD backlight. Range should be 11.9V to 13.5V
measured at this connector.
+5V standby
+5V standby power; powers board when in standby mode.
PS_ON
Power Supply ON. Feedback pin for external ATX supply, when needed;
pulled low when on-board power is inactive.
Poseidon in the standard, mid-range power input configuration supports a voltage range from +4.75V to +5.25V,
with some restrictions.
The “+12V” power supply input is intended for all on-board and board-controlled 12V power supplies, including the
PC/104-
Plus
12V supplies, the external hard drive power supply (through connector J15, described above), and the
LCD backlight. If these devices are not used, the “+12V” input may be left unconnected.
Make certain that your power supply has enough current capacity to drive your system. The Poseidon requires 12 to
20 Watts or more, depending on which external devices are connected to the board. This could require over 4A on
the “+Vin” line at minimum voltage inputs. In particular, many disk drives need extra current during startup. If
your system fails to boot properly or if disk accesses do not work correctly, the first thing to check is the power
supply voltage level. Many boot-up problems are caused simply by insufficient voltage due to excess current draw
on the “+Vin” supply during initialization.
Mu5V and ground pins are provided for extra current carrying capacity, if needed. Each pin is rated at 3A
max (15W). For the Poseidon CPU with a moderate I/O device complement (basic hard drive, key board, mouse,
USB devices, and a network PC/104-
Plus
card, for example).
ATX control enables the +5V and +12V power to be switched ON and OFF with an external momentary switch. A
short press on the switch turns ON power, and holding the switch on for four seconds or longer turns OFF power
(See the Utility Header description for connector CN18, above).
USB 2.0 Connectors
Connector CN21 is a 2x10 pin headers for connecting USB 0/1 and USB 2/3, each providing USB 2.0 480Mbps
maximum transfer rates.
-
1
2
Shield
Shield
3
4
Shield
USB3 data+
5
6
USB2 data+
USB3 data-
7
8
USB2 data-
USB2/3 power
9
10 USB2/3 power
- 11
12 Shield
Shield 13
14 Shield
USB1 data+ 15
16 USB0 data+
USB1 data- 17
18 USB0 data-
USB0/1 power 19
20 USB0/1 power
Diamond Systems Corporation
Poseidon User Manual
Page 31
