Autonomous Standby; Purpose; Enabling And Disabling Autonomous Standby; Events That Wake The Wireless Cpu - Wavecom GR64 UART Sleep Protocols Application Note

3

Autonomous Standby

3.1

Purpose

Like Standby Handshaking, Autonomous Standby enables the Wireless CPU® to enter
low power mode during idle periods. However, instead of using the UART signal lines
to request or acknowledge sleep mode, the Wireless CPU® enters sleep mode without
Host interaction, or autonomously. An inactivity timer determines the minimum time
that the Wireless CPU® will delay before entering sleep mode.
The only UART signals required between the Host and the Wireless CPU® are DFM1,
DTM1 and ground.
By default, Autonomous Standby is not enabled at Wireless CPU® start-up.
3.2

Enabling and Disabling Autonomous Standby

Autonomous Standby can be enabled by using the AT command AT*E2RS232 with a
<Sel> parameter of 4. (refer to the GR64 & GS64 AT Command Manual for details).
Autonomous Standby can be disabled by using the AT command AT*E2RS232 with a
<Sel> parameter of 0. The inactivity delay is determined by the <itimr> parameter.
Autonomous Standby can also be enabled or disabled from embedded applications
by using the spm() function. Spm() also sets the inactivity delay.
Whether enabled by AT command or embedded application, the Wireless CPU® will
attempt to sleep whenever possible. The delay before entering sleep mode will never
be less than the inactivity delay setting, but may be longer. When the Wireless CPU®
is first powered it will generally attempt network registration, then typically the Host
and Wireless CPU® will perform some configuration procedures and a further
exchange of communication. This may take between ten and thirty seconds, longer if
there is network congestion. We suggest waiting until after this preliminary activity
before enabling Autonomous Standby.
3.3 Events that wake the Wireless CPU®
During sleep mode, the Wireless CPU® is awakened for the following reasons:
APPLICATION NOTE
GR/GS64 UART Sleep Protocols
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