rtd CML24BT cpuModules, User Manual

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54 CML24BT cpuModule BDM-610000084 Rev B
Power Supplies and VIO
+5 V — +5 V supply connected to the Auxiliary Power Connector ( CN3 ) +5 V supply input.
+12 V — Pass-t12 V supply; not connected on this cpuModule
–12 V — Pass-through –12 V supply rail; not used on this cpuModule
+3.3 V — Pass-t3.3 V supply rail; not used on this cpuModule
VIO — This signal is typically the I/O power to the bus drivers on a PCI bus card, or used by the clamp diodes
on a PCI bus card. This is always driven by the cpuModule. By default, the signaling level is set to +3.3 V. For
information on configuring VIO for +5 V, contact RTD Technical Support.
ATX Power Management Signals (optional)
If an ATX power supply is connected to the system, the following signals listed below may be used to wake the
system from low power modes. For more information on these signals, refer to the
Power Management section
on page 65.
+5V_STBY — Some low power modes require that +5 V standby power is applied to the cpuModule during
the wake event. This signal is an input to the CPU.
PME# — Power Management Event input
PSON# — This is an active low open-drain output used to turn the power supply on when the system is
exiting a low power state.
WARNING The power +5 V and +12 V power rails are the only supply inputs required for board
operation. However, while the PCI bus connector ( CN16 ) has +5 V and +12 V pins, the +12 V pin is not
connected, as the pin does not meet the cpuModule’s current requirement. for +12 V. The cpuModule
must be powered by either one of the PCIe/104 Type 2 Connectors (
CN1 or CN2 ) or the Auxiliary Power
Connector ( CN3 ) to operate. If the cpuModule is only connected via the PCI connector, the cpuModule’s
LED will turn red, indicating that the +12 V input rail is not present.