Sleep support Sleep parameters
Digi XBee3® 802.15.4 RF Module User Guide
77
Cyclic Sleep with Pin Wake-up mode (SM = 5)
Use this mode to wake a sleeping remote device through either the RF interface or by de-asserting
SLEEP_RQ for event-driven communications. The cyclic sleep mode works as described previously with
the addition of a pin-controlled wake-up at the remote device.
The SLEEP_RQ pin is level-triggered. The device wakes when a low is detected then sets CTS low as
soon as it is ready to transmit or receive. The device stays awake as long as SLEEP_RQ is low; once
SLEEP_RQ goes high the device returns to cyclic sleep operation.
Any activity resets the ST command timer, so the device goes back to sleep only after there is no
activity for the duration of the timer.
Sleep parameters
The following AT commands are associated with the sleep modes. See the linked commands for the
parameter's description, range and default values.
n SM command
n SP command
n ST command
n DP (Disassociated Cyclic Sleep Period)
n SO command
Sleep current
The following table shows the sleep current during the XBee3 802.15.4 RF Module sleep modes.
Sleep mode
SM command setting
Sleep current
Pin sleep
1
Cyclic sleep 4 <1 µA @ 25 ºC
Cyclic sleep with pin wake-up 5 <1 µA @ 25 ºC
You can make devices use low sleep current by driving PWM outputs high during sleep and by using
internal pull-ups/pull-downs on disabled/unused pins.
The sleep pins are set up for sleeping as specified in the following section, Sleep pins. Additionally, pins
that are outputs (other than PWM outputs) continue to output the same levels during sleep. Normally,
this means that pins configured for output high or low will output high or low accordingly. However, if
I/O line passing overrides the output, the output level is maintained during the sleep time.
Sleep pins
The following table describes the three external device pins associated with sleep. Refer to the XBee3
Hardware Reference Guide. See the XBee3 RF Module Hardware Reference Manual for the pinout of your
device.
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