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Java Terminals Hardware Interface Overview
3.10 Automatic thermal shutdown
39
EHSxT_BGS5T_HIO_v03
2016-05-26
Confidential / Released
Page 36 of 50
3.10
Automatic thermal shutdown
An on-board NTC measures the temperature of the built-in Java module. If over- or undertem-
perature is detected on the module the Java Terminals automatically shut down to avoid ther-
mal damage to the system.
The automatic shutdown procedure is equivalent to the power-down initiated with the AT^SM-
SO command, i.e. Java Terminals log off from the network and the software enters a secure
state avoiding loss of data.
Alert messages transmitted before the Java Terminals switch off are implemented as Unsolic-
ited Result codes (URCs). For details see the description of AT^SCTM command provided in
The watchdog can be configured to restart the Java Terminals after a defined period of time.
3.11
Hardware Watchdog
The Java Terminals feature a programmable hardware watchdog that permanently monitors
the terminals hardware and can be configured to react to various hardware states. The watch-
dog may for example be configured to periodically restart the terminal, independent of its cur-
rent operating state.
3.12
RTC
The internal Real Time Clock (RTC) of the Java Terminals retains the time and date and han-
dles the alarm function. The AT+CCLK command serves to set the time and date, and AT+CA-
LA specifies a reminder message or sets an alarm for the .Java Terminals to wake up. See
for details.
A dedicated voltage regulator backs up the RTC even in Power Down mode and enables Java
Terminals to keep track of time and date.
However, please note that the Alarm function described in
, Section AT+CALA, will only work
if there is no “auto ignition“ connection active between IGT_IN pin and PLUS pin at the power
supply unit that will automatically trigger a restart (see
). Otherwise, the AT+CALA
command can only be used to set a reminder message, but not to configure the Java Terminals
to wake up from Power Down mode.
