Cinterion
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LTE Terminals Hardware Interface Description
8 Appendix A: (Hardware) Watchdog
101
ELSxT_HID_v04 2018-09-04
Confidential / Preliminary
Page 73 of 102
8 Appendix A: (Hardware) Watchdog
The watchdog is part of the LTE Terminals and connected to the LTE module itself (see also
Figure 6). It can be used to
• Safely reset the module in certain conditions
• Restart the module when it has turned off
• Configure level shifter‘s GPIO directions and DSR0/ADC1_IN availability at the GPIO con-
nector
The complete watchdog functionality can be configured by means of special watchdog config-
uration commands (i.e., WD commands) that are passed to the watchdog via the serial TXD0
line. For details on how to configure the complete watchdog functionality see Section 8.3.
A qualified set of configuration commands - level shifter‘s GPIO directions, DSR0/ADC1_IN us-
age, trigger delay and firmware infos - can be specified by means of a special write/read pro-
tocol handled by the watchdog‘s I
2
C interface. For details on how to configure the watchdog via
I
2
C interface see Section 8.4.
The below Figure 27 illustrates the various ways the watchdog may be accessed and config-
ured.
Figure 27: Hardware watchdog configuration
Note: Unless the complete configuration scope is required, the qualified watchdog configura-
tion via I
2
C interface should be used.
Hardware watchdog
Resets/Restarts the
Java module under
certain conditions and
configures GPIOs
RS-232 connector
GPIO connector
Java module
Qualified watchdog
configuration
Java Terminal
USB-B connector
Qualified watchdog configuration via Java module’s I
2
C lines using AT^SSPI command
(Baud rate has to be >1200bps - if employing ASC0 interface)
RS-485 lines
ASC1 lines
Complete watchdog
configuration via TXD0 line using
WD commands (Baud rate has to
be =1200bps)
USB lines
ASC0 lines
I
2
C lines
I
2
C interface
(Address: 0x6A)
TXD0 interface
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