COMe-cVR6 – User Guide Rev. 1.5
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3.1.3.
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 properly.
Table 52: 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 will cause a direct switch to S5 (Power Failure).
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”.
3.1.4.
Power Supply Modes
Setting the power supply controls enables the COMe-cVR6 to operating in either ATX power mode or in single power
supply mode.
3.1.4.1.
ATX Mode
To start the module in ATX mode and power VCC, follow the steps 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 set the PWR_OK to high and power VCC.
The PS_ON# signal, generated by SUS_S3# (A15), indicates that the system is in the 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 8.5 V.
Table 53: ATX Mode Settings
State
PWRBTN#
PWR_OK
V5_StdBy
PS_ON#
VCC
G3
x
x
0V
x
0 V
S5
high
low
5V
high
0 V
S5
→
S0
PWRBTN Event
low
→
high
5V
high
→
low
0 V
→
VCC
S0
high
high
5V
low
VCC
x – Signals are not relevant for the specific power state. It makes no difference if the signal is connected or open.
