Watchdog; Real-Time Clock; Power Management - Digi ConnectCore 8X Hardware Reference Manual

The ConnectCore 8X System-on-Module
External 32KHz clock output
The MCA_CLKOUT32K pin is a 32.768 Hz square wave output that can be used as clock input by
peripherals requiring a low-frequency, high-accuracy clock.
Note The default configuration of the MCA_CLKOUT32K pin is as a 32kHz clock output. See the
MCA software documentation for additional information about how to control the function of this pin.
Note that the 32KHz clock output continues normal operation in low power modes (suspend and
power off). Therefore, if the 32KHz clock output is enabled during normal operation but is not required
for low power operation, Digi recommends using the software to disable it before entering low power
in order to minimize power consumption, and re-enable it when resuming normal operation.

Watchdog

The MCA implements a watchdog timer in its firmware. The MCA watchdog resets the system, or only
the i.MX 8X CPU, if the software running on the main processor fails to execute properly and does not
reset the watchdog timer on time.
The main features of the MCA watchdog include:
Configurable timeout between 1 and 255 seconds.
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Configurable to generate interrupt or system reset.
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Configurable to generate full-system reset (including the MCA itself) or CPU-only reset. Full-
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system reset can include a PMIC off/on, depending on the device configuration.
See the MCA software documentation for additional information about how to configure and access
the watchdog timer.

Real-time clock

The MCA implements a Real-Time Clock (RTC) in its firmware. The i.MX 8X CPU internal RTCs are
disabled by default because the MCA RTC is preferred due to its superior power consumption
efficiency. To preserve the date during power-off, you must connect a coin cell battery following the
design notes provided in
The main features of the MCA RTC include:
Date/time registers to keep the system time (backed up by the coin cell battery).
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Programmable alarm to generate an interrupt. This alarm can be used to wake the system
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from low power modes (suspend and power off).
See the MCA software documentation for additional information about how to configure and access
the watchdog timer.

Power management

The MCA plays a key role in the power management activities of the ConnectCore 8X module. In
cooperation with the i.MX 8X processor, the MCA controls the power states of the PMIC and provides
multiple wake up sources to transition between power modes. It also allocates dedicated signals to
capture power events and indicate the system power state, allowing you to control external power
sources and indicators.
ConnectCore® 8X System-on-Module Hardware Reference Manual
System-on-Module input power
The Micro Controller Assist™ hardware
supply.
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