Kontron COMe-cOHXX - Manual (Page 49)

Kontron COMe-cOH2/COMe-cOH6 User’s Guide
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44
4.1.15 Power Control Interface
VCC_12V is allowed to range from 4.75V to 18V. This range is above and beyond
the requirements of the COM Express specification.
Power Good (PWR_OK)
The COMe-cOH# COM provides an external input for a power-good signal (pin
B24). The implementation of this subsystem complies with the COM Express®
Specification. PWR_OK is internally pulled up to 3.3V and must be sampled as
logic high to power on the module.
Power Button (PWRBTN#)
The power button (pin B12) is available through the module connector as
defined in the COM Express connector pin-out list.
To power-off the module, press and hold the power button for at least four
seconds.
Reset Button (SYS_RESET#)
The reset button (pin B49) is available through the module connector as
defined in the pin-out list. The module stays in reset as long as SYS_RESET#
is grounded.
Power Supply
The COMe-cOH# COM has a wide range of power inputs, from 4.75V to 18V DC. The
supply voltage is applied through the VCC pins on the module connector. In
ATX mode the 5V standby voltage range is from 4.75V to 5.25V. RTC power is
provided on the VCC RTC pins. VCC_12V may or may not collapse in suspend
states S3, S4, S5
ATX Mode / Single Supply Mode
ATX Mode:
When an ATX power supply is connected, PWR_OK is set to low-level and VCC is
off. Pressing the power button enables the ATX PSU setting PWR_OK to high-
level and powers on VCC. The ATX PSU is controlled by the PS_ON# signal,
which is generated by SUS_S3#.
Table 12: ATX Mode