ZWIR4512
© 2016 Integrated Device Technology, Inc.
Table 2.1 Power Modes Overview
Mode Wakeup Clock Context
I/O Transceiver
Source Time MCU Core Peripherals
Run On On
Retained As configured On
Sleep Any IRQ 1.8 µs Off Off
4)
Retained As configured Off
4)
Stop
RTC IRQ
External IRQ
5.4 µs Off Off Retained As configured Off
4)
Standby
RTC IRQ
Wakeup pin
50 µs Off Off Lost Analog input Off
1) Refers to the status of the RAM and peripheral register contents after wakeup – the backup registers of the MCU are
always available.
2) Clock is enabled for all peripherals that have been enabled by application code and all peripherals that are used by the library.
3) Can be powered off by application code.
4) Remains if peripheral/transceiver is selected as wakeup source.
2.4.1. Run Mode
In Run Mode, all functions of the module are available. The microcontroller and all its peripherals are powered.
Typically the transceiver is also powered, but it can be disabled by software. The module enters Run Mode
automatically after startup. The application software must switch to one of the other operating modes if required.
2.4.2. Sleep Mode
In Sleep Mode, the microcontroller core is not clocked. The power state of the transceiver and the microcontroller
peripherals depends on the wakeup configuration. All peripherals that are selected as a wakeup source continue
to operate. After wakeup, the application program continues execution at the position it was stopped. Sleep Mode
allows reacting to external events such as the reception of data, external interrupts, or timer events. The power
consumption in this mode strongly depends on which peripherals are enabled. The I/O configuration is not
changed during Sleep Mode.
2.4.3. Stop Mode
Stop Mode is an ultra-low-power mode with RAM retention. The MCU core and the MCU peripherals are not
clocked. Only the internal real-time clock or any external pin can be used for triggering wakeup from Stop Mode.
After wakeup, the program continues execution at the position it was stopped. In Stop Mode, all I/Os remain in
the configuration that was active when entering Stop Mode.
2.4.4. Standby Mode
Standby Mode is the lowest power mode. The transceiver and all microcontroller peripherals are consequently
powered off. RAM contents are lost. Waking up from Standby Mode can be triggered by a real-time-timer event
or by one dedicated pin. When going to Standby Mode, all I/Os are put into analog input mode, so the application
circuit must ensure that external components receive defined signal levels if required. When the module exits
Standby Mode, it is restarted from the reset handler in the same sequence as the restart after power-on or after
the reset button has been pressed.