Power Modes; Off; Active; Sleep - VeriFone e355 User And Best Practices Manual

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OWER

Power Modes

Power Modes Power modes are independent in e355 and attached smart device. There are
three power states in e355—OFF, ACTIVE, and SLEEP.

Off

Processor and its peripherals are powered off. When it is next powered on, the
unit goes though full boot-up cycle, SW stack initialization and applications
executing from "main" routine. Off state transition is blocked when e355 is
connected to smart device, either via USB or BT.

Active

There are two active states for e355.
Active Run
The unit is in the Active Run state whenever an application is running. The
processor will run at full speed as long as any application is ready to run. The
"core" of the microprocessor is consuming full power. Even in this state, other
parts of the system may be shut down or at least consuming less than the
maximum amount of power.
Active Idle
The unit is in Active Idle state when applications are suspended (by calling
wait_event or SVC_WAIT), the processor is then slowed. This happens
immediately, and just as quickly, the system can transition back to Active Run
state when work arrives to wake up an application. It is not possible to distinguish
between Active Run and the early stage of Active Idle state. They appear the
same but the system clock is running at a lower clock speed, and other internal
mechanisms are shut down when not being used. The terminal consumes
considerably less power than when it is Active Run.
The e355 goes into Active Idle state after all the applications are suspended for 20
seconds (default *POW configuration setting). Transition is automatic to next sleep
state (snooze or deep sleep). E355 LCD display transitions to dim in the active
Idle state.

Sleep

Two sleep states are supported by e355—snooze and deep sleep.
Snooze
Snooze state is applicable only when Lightning/USB interface is connected to
smart device. USB peripheral is always active and all other peripherals are
powered down in this state. USB data traffic instantly wakes e355 to full active
run, without loss of packets or data. e355 LCD display transitions to dark (Off) in
deep sleep state.
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