User manual

ATHENA CPU User Manual V1.40 Page 12
4.3 Input Power – J11
1 +5V In
2 Ground
3 Ground
4 +12V In
5 Ground
6 +5V In
7 -12V In
8 -5V In
9 ATX Control
Table 3: J11 – Input Power Connector Pinout
Input power for Athena may be supplied either through J11 from an external supply or directly
through the PC/104 bus power pins if a PC/104 power supply is used with the CPU.
Athena requires only +5VDC input power to operate. All other required voltages are generated on
board with miniature switching regulators. However since the PC/104 bus includes pins for ±5V
and ±12V, these voltages may be supplied through J11 if needed. The +5V and +12V voltages
are controlled by the ATX power manager switches, while -5V and -12V are routed directly to the
corresponding pins on PC/104 bus and are not controlled by the ATX function.
Make sure that the power supply used has enough current capacity to drive your system. The
Athena CPU requires up to 2A on the +5V line for the 400Mhz configuration (2.7A for the 660Mhz
configuration.) If you have a disk drive or other modules connected, you need additional power. In
particular, many disk drives need extra current during startup. If your system fails to boot properly,
or if disk accesses do not work properly, 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 +5V supply.
Multiple +5V and Ground pins are provided for extra current carrying capacity if needed. Each pin
is rated at 3A max (15W). For the Athena CPU and panel I/O board 3A is sufficient, so +5 and
Ground require only a single wire each. In this case the first 4 pins may be connected to a
standard 4-pin miniature PC power connector if desired. Be advised that some voltage will be
dropped in the wire depending on the wire guage (AWG).
For a larger PC/104 stack the total power requirements should be calculated to determine
whether additional wires are necessary.
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 will turn on power, and holding the switch on for 4
seconds or longer will turn off power.
Diamond Systems’ cable no. 698009 mates with J11. It provides 9 color-coded wires with stripped
and tinned leads for connection to user-supplied power sources. This cable may also be used
with Diamond Systems’ Jupiter-MM series power supplies in vehicle-based applications. In this
configuration, the input power is supplied to the Jupiter-MM board, and the Jupiter-MM output
power is connected to J11 on the CPU using cable 698009. When used in this way, make sure
the two red +5V wires are both connected to the +5V output screw terminal on Jupiter-MM and
the Jupiter-MM is not plugged onto the PC/104 stack.