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4 Features and Interfaces
4.1
Power Control
Power Supply
The nanoETXexpress-SP has a wide range power input from 4.75 - 14V. The supply voltage is applied through the VCC pins
(VCC) of the module connector.
Power Button (PWRBTN#)
The power button (Pin B12) is available through the module connector described in the pinout list. To start the module via
Power Button the PWRBTN# signal must be at least 50ms (50ms ≤ t < 4s) at low level (Power Button Event).
Pressing the power button for at least 4seconds will turn off power to the module (Power Button Override).
Power Good (PWR_OK)
The nanoETXexpress-SP 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.
Reset Button (SYS_RESET#)
The reset button (Pin B49) is available through the module connector described in the pinout list. The module will stay in
reset as long as SYS_RESET# is grounded.
ATX Mode / Single Supply Mode
ATX Mode: By connecting an ATX power supply PWR_OK is set to low level and VCC is off. Press the Power Button to enable
the ATX PSU setting PWR_OK to high level and powering on VCC. The ATX PSU is controlled by the PS_ON# signal which is
generated by SUS_S3# via inversion.
State
PWRBTN#
PWR_OK
G3
x
x
S5
high
low
→
→
S5
S0
PWRBTN Event
low
high
S0
high
high
Single Supply Mode or automatic power on after power loss: In single supply mode the module will start automatically
when VCC power is connected and Power Good input is open or at high level (internal PU to 3.3V). PS_ON# is not used and
5V_StdBy is not important (no difference if connected or not) in this mode.
To power on the module from S5 state press the power button or reconnect VCC
State
PWRBTN#
PWR_OK
G3
x
x
→
G3
S0
high
open / high
S5
high
open / high
→
S5
S0
PWRBTN Event
open / high
All columns marked with an "x" are not important for the specific power state.
All ground pins have to be tied to the ground plane of the carrier board.
26
V5_StdBy
PS_ON#
VCC
0V
x
0V
5V
high
0V
→
→
5V
high
low
0 V VCC
5V
low
VCC
V5_StdBy
VCC
x
0
x
connecting VCC
x
VCC
x
reconnecting VCC
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