BDM-610000075
Rev B
Chapter 4: Using the cpuModule
83
•
Resume on RTC Alarm:
The RTC Alarm allows the system to turn on at a certain time every day.
AT vs. ATX Power Supplies
Both AT and ATX power supplies may be used with the CMX32M cpuModule, however AT power supplies do
not provide any standby power to the cpuModule. When an AT power supply is used to power the system, low
power modes that require a standby power to wake the system will not be fully supported.
ATX power supplies do provide a standby power, thus allowing the system to utilize all low power modes
supported by the hardware. When an ATX supply is used to power the cpuModule, lower power modes can be
achieved. During these low power modes, the standby power from the ATX power supply provides power to a
small circuit on the CPU, which is used to watch for a system wake event.
ATX Power Supply Signals
The auxiliary power connector (
CN3
) provides two ATX style signals., +5V Standby and PSON#. The +5V
Standby rail is used to power certain parts of the cpuModule when the main power supply is turned off, i.e.
during Suspend-to-RAM (S3), Hibernate (S4), or Soft-Off (S5) power modes. The PSON# signal is an active low
open-drain output that signals the power supply to turn on. Use of these signals allows the power consumption
to drop to below 1W during standby modes, and still enable any of the wake events.
Reducing Power Consumption
In addition to the CPU’s low power modes, power consumption can further be reduced by making some
modifications to the BIOS setup. When the following features are modified, the CPU’s power consumption will
decreases:
•
CPU Speed:
Setting the processor to its minimum speed in the BIOS will reduce power consumption
•
Memory Speed:
Changing the DDR DRAM clock frequency will reduce power consumption, however
memory performance will also be reduced.
•
Ethernet:
Can be disabled in the BIOS
•
Serial Ports:
Can be disabled in the BIOS
•
LVDS Flat Panel:
If an LVDS panel is not connected to the cpuModule while using a VGA monitor,
setting the BIOS to use only a CRT (VGA) monitor will reduce power consumption.
•
Fan Mode:
Set the fan to auto mode so it is used only when the processor reaches high temperatures.
This option will only effect the fan if it is connected to the switched fan power connector (
CN15
).
•
Multi-Color LED:
Can be disabled in the BIOS
Summary of Contents for BDM-610000075
Page 3: ... Accessing the Analog World www rtd com ISO9001 and AS9100 Certified CMX32M cpuModules ...
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