Sleep Commands; Fh (Force Wakeup Initializer); Ht (Time Before Wake-Up Initializer) - Digi XBee-PRO S3 User Manual

Configuration and commands

Sleep commands

The following commands are sleep commands.

FH (Force Wakeup Initializer)

Forces the device to send a wake-up initializer on the next transmission.
Only use FH with cyclic sleep modes active on remote devices.
You do not need to issue the WR (Write) command with FH.
Binary command
0x0D (13 decimal)
Parameter range
N/A
Default
N/A
Bytes returned
N/A

HT (Time before Wake-up Initializer)

Sets or displays the time of inactivity (no serial or RF data is sent or received) before a transmitting
(TX) RF device sends a wake-up initializer. The main purpose of this command is to prevent devices
from sending the Long Header with every data packet. For more information on long headers, see
(Wakeup Initializer
For RX devices operating in Cyclic Sleep mode (SM = 4-8), set HT to be shorter than the ST command.
The TX device sends a wake-up initializer, which instructs all receiving (RX) devices to remain awake
to receive RF data.
From the perspective of the RX device: after HT time elapses and the inactivity timeout (ST command)
is met, the RX device goes into cyclic sleep. In cyclic sleep, the RX device wakes once per sleep interval
(SM command) to check for a wake-up initializer. When it detects a wake-up initializer, the device
stays awake to receive data. The wake-up initializer must be longer than the cyclic sleep interval to
ensure that sleeping devices detect incoming data.
When HT time elapses, the TX device knows it needs to send a wake-up initializer for all RX devices to
remain awake and receive the next transmission.
Binary command
0x03 (3 decimal)
Parameter range
0 - 0xFFFF [x 100 ms]
Default
0xFFFF (wake-up initializer will not be sent)
Bytes returned
2
XBee®-PRO 900HP/XSC RF Modules
Timer).
Sleep commands
LH
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