Kontron ETXexpress-AI User Manual

Page 66

Kontron ETXexpress-AI User’s Guide

For further details, please refer to the Intel® QM57 Platform
Controller Hub External Design Specification (EDS) on the Intel
website at

http://www.intel.com

4.4.10

Power Control Interface

Power Good (PWR_OK)

The ETXexpress®-AI 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
high-level to power on the module.

Power Button (PWRBTN#)

The power button (pin B12) is available through the module connector as
defined in the pin-out list. To start the module using the power button, the
PWRBTN# signal must be at least 50ms (50ms ≤ t < 4sec) at low-level power.

You can put the module into power-off mode by pressing 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 ETXexpress®-AI COM has a wide range of power inputs, from 8V to 18V DC.
The supply voltage is applied through 42 pins (VCC) on the module connector.
In ATX mode with 5V standby voltage, the VCC input must be higher than the
standby voltage.

In general, single supply mode means the module starts as soon as power is
applied to the module and ATX mode is for power button-controlled operation.

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# via inversion.