User's Manual

HiLo3G-850 User Manual
04 March 2011 - Page 27 / 36
4.4.1 UART Interface
To stop the module, use the AT command AT+CPOF. If the PWON is not pulled down the module will switch to OFF
mode after the AT command, otherwise the module restarts immediately (an OFF sequence is performed followed by a
power ON sequence).
Figure 28: Power off sequence for PWON, VGPIO and CTS
4.4.2 USB Interface
As the module can also start when an USB cable is plugged, the sequence to stop the module needs the USB interface to be
OFF or VBUS disconnected just after the command is sent and acknowledged by the module. Thus, to stop the module
when the USB interface is being used, use the AT command AT+CPOF, then disconnect VBUS (unplug the USB cable or
use a commanded switch to switch off VBUS) signal when the module acknowledges (responds OK) the command,
otherwise the module restarts immediately (an OFF sequence is performed followed by a power ON sequence).
4.5 Sleep Mode
The AT command ―AT+KSLEEP‖ allows configuring the sleep mode.
When AT+KSLEEP=1 has been configured:
• The HiLo module decides by itself when it enters in sleep mode (no more task running).
• ―0x00‖ character on serial link wakes up the HiLo3G-850 module.
When AT+KSLEEP=0 has been configured:
• The HiLo3G-850 module is active when DTR signal is active (low electrical level).
• When DTR is deactivated (high electrical level), the HiLo3G-850 module enters in sleep mode after a while.
• On DTR activation (low electrical level), the HiLo3G-850 module wakes up.
When AT+KSLEEP=2 has been configured:
• The HiLo3G-850 module will never enter sleep mode.
In sleep mode the module reduces its power consumption and remains waiting for the wake up signals either from the
network, from the operating system or from the host controller.
Note: The module cannot enter sleep mode if USB bus is connected.
5. ESD & EMC Recommendation
Using human body model from JEDEC JESD 22-A114 standard, HiLo3G-850 can hold 2KV on each of the 40 pins and