At vs. atx power supplies, Atx power supply signals – IBM BDM-610000049 User Manual
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CMX158886 cpuModule
BDM-610000049
Rev G
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Resume on aDIO:
This option allows the system to use an aDIO Strobe, Match, or Event interrupt to
generate a wake event. This event can wake the CPU from any power-down mode, including Soft-Off
(S5). For more information, refer to the section titled
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Resume on PME#:
When enabled, the system can wake when a signal is applied to the External Power
Management connector (CN12). This includes wake-up on onboard LAN controller. The PME# signal
is also available on the PC/104-
Plus (PCI) bus connector.
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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 CMX158886 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.