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SUS_S3#
The SUS_S3# (pin 18) signal shuts off power to all runtime system components that are not maintained during suspend mode. This signal
is an output signal and is connected to the Power Management Integrated Circuit (PMIC). See section 9.16 “Power Management” for more
information.
PWRBTN#
When using ATX-style power supplies, PWRBTN# (pin 20) is used to connect to a momentary-contact, active-low debounced push-button input
while the other terminal on the push-button must be connected to ground. This signal is internally pulled up to 3V_SB using a 10k resistor. When
PWRBTN# is asserted it indicates that an operator wants to turn the power on or off.
Note
The conga-QMX6 boots up immediately power is applied to the module’s +5v input rail. To shutdown the system, use the the linux command
“poweroff”. Depending on the operating system, the shutdown can also be performed by pressing the power button. If the system is in shutdown
or standby state, pressing the power button restores the system back to full-on state. When the chip main power supply is Off, a button press
greater in duration than 750 ms asserts an output signal to request power from a power IC to power up the SoC.
If it’s desired to keep the system switched off even when the +5V input power rail is initially powered on (ATX-style), an external logic has to be
used that prevents the system from booting by means of the power good signal (PWGIN). It is the responsibility of the external logic to release
the PWGIN signal, when the desired event (e.g. pressing the power button) occurs.
Power Supply Implementation Guidelines
5 volt input power is the sole operational power source for the conga-QMX6. The remaining necessary voltages are internally generated on the
module using onboard voltage regulators. When designing a power supply for a conga-QMX6 application, a carrier board designer should be
aware of the important information below:
• It has been noticed that on some occasions, problems occur when using a 5V power supply that produces non monotonic voltage when
powered up. The problem is that some internal circuits on the module (e.g. clock-generator chips) will generate their own reset signals
when the supply voltage exceeds a certain voltage threshold. A voltage dip after passing this threshold may lead to these circuits becoming
confused resulting in a malfunction. It must be mentioned that this problem is quite rare but has been observed in some mobile power supply
applications. The best way to ensure that this problem is not encountered is to observe the power supply rise waveform through the use
of an oscilloscope to determine if the rise is indeed monotonic and does not have any dips. This should be done during the power supply
qualification phase therefore ensuring that the above mentioned problem doesn’t arise in the application. For more information about this
issue visit www.formfactors.org and view page 25 figure 7 of the document “ATX12V Power Supply Design Guide V2.2”.
