COMe-mAL10 – User Guide, Rev. 1.3
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2.4.3.
Power Supply Control Settings
The power supply control settings are set in the BIOS and enable the module to shut down, rest and wake from
standby.
The following table lists the implemented power supply control settings.
Power Button
(PWRBTN#)
Pin
B12
To start the module using the power button, the PWRBTN# signal must be at
least 50 ms (50 ms ≤ t < 4 s, typical 400 ms) at low level (Power Button Event).
Pressing the power button for at least four seconds turns off power to the
module (Power Button Override).
Power Good
(PWR_OK)
Pin
B24
PWR_OK is internally pulled up to 3.3 V and must be at the high level to power
on the module. This can be driven low to hold the module from powering up as
long as needed. The carrier needs to release the signal when ready.
Low level prevents the module from entering the S0 state. A falling edge during
S0 causes a direct switch to S5 (Power Failure). After a power failure (PWR_OK
going HIGH again) the module will not start up automatically.
Reset Button
(SYS_RESET#)
Pin
B49
When the SYS_RESET# pin is detected active (falling edge triggered), it allows
the processor to perform a “graceful” reset, by waiting up to 25 ms for the
SMBus to go idle before forcing a reset, even though activity is still occurring.
Once the reset is asserted, it remains asserted for 5 ms to 6 ms regardless of
whether the SYS_RESET# input remains asserted or not.
SM-Bus Alert
(SMB_ALERT#)
Pin
B15
With an external battery manager present and SMB_ALERT #connected, the
module always powers on even if the BIOS switch “After Power Fail” is set to
“Stay Off”.
The COMe-mAL10 includes an additional cold reset during the first cold boot after a
complete power loss (including battery voltage). This additional reset will not happen on
any subsequent warm or cold reboots.
2.4.4.
Power Supply Modes
Setting the power supply controls enables the module to operating in either ATX power mode or in single power
supply mode.
2.4.4.1.
ATX Mode
To start the module in ATX mode and power VCC, follow the step below.
1.
Connect the ATX PSU with VCC and 5 VSB to set PWR_OK to low and VCC to 0 V.
2.
Press the power button to sets the PWR_OK to high and powers VCC.
The PS_ON# signal generated by SUS_S3# (A15) indicates that the system is in Suspend to RAM state. An inverted
copy of SUS_S3# on the carrier board may be used to enable non-standby power on a typical ATX supply. The input
voltage must always be higher than 5 V standby (VCC > 5 VSB) for Computer-On-Modules supporting a wide input
voltage range down to 4.75 V.
