Specifications
Table Of Contents
- Contents
- Tables
- Figures
- 1 Introduction
- 2 Interface Characteristics
- 2.1 Application Interface
- 2.2 RF Antenna Interface
- 2.3 Sample Application
- 3 Operating Characteristics
- 3.1 Operating Modes
- 3.2 Power Up/Power Down Scenarios
- 3.3 Power Saving
- 3.4 Power Supply
- 3.5 Operating Temperatures
- 3.6 Electrostatic Discharge
- 3.7 Blocking against RF on Interface Lines
- 3.8 Reliability Characteristics
- 4 Mechanical Dimensions, Mounting and Packaging
- 5 Regulatory and Type Approval Information
- 6 Document Information
- 7 Appendix
Cinterion
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ELS81-US Hardware Interface Description
3.2 Power Up/Power Down Scenarios
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els81-us_hid_v01.004 2017-09-27
Confidential / Preliminary
Page 62 of 107
3.2.4 Turn off ELS81-US
To switch the module off the following procedures may be used:
•
Software controlled shutdown procedure: Software controlled by sending an AT command
over the serial application interface. See Section 3.2.4.1.
•
Hardware controlled shutdown procedure: Hardware controlled by disconnecting the mod-
ule‘s power supply lines BATT+ (see Section 3.2.1.1).
•
Automatic shutdown (software controlled): See Section 3.2.5
- Takes effect if ELS81-US board temperature or voltage levels exceed a critical limit.
3.2.4.1 Switch off ELS81-US Using AT Command
The best and safest approach to powering down ELS81-US is to issue the appropriate AT com-
mand. This procedure lets ELS81-US log off from the network and allows the software to enter
into a secure state and safe data before disconnecting the power supply. The mode is referred
to as Power Down mode. In this mode, only the RTC stays active. After sending the switch off
command AT^SMSO, be sure not to enter any further AT commands until the module was re-
started.
CAUTION: Be sure not to disconnect the operating voltage V
BATT+
before V180 pad has gone
low. Otherwise you run the risk of losing data, or in some rare cases even to render the module
inoperable.
To monitor the V180 line, it is recommended to implement a power indication circuit as de-
scribed in Section 2.1.13.2.
While ELS81-US is in Power Down mode the application interface is switched off and must not
be fed from any other voltage source.
Therefore, your application must be designed to
avoid any current flow into any digital pads of the application interface.