Gemalto Cinterion ELS31T-J, Hardware Interface Description, Page: 86 / 102

Cinterion
®
LTE Terminals Hardware Interface Description
8.4 Qualified Watchdog Configuration
101
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ELSxT_HID_v04 2018-09-04
Confidential / Preliminary
Page 86 of 102
8.4 Qualified Watchdog Configuration
While the complete watchdog functionality may be configured via TXD0 line of the ASC0 inter-
face (for details see
Section 8.3 ), a qualified set of configuration commands can also be spec-
ified via the watchdog‘s I
2
C interface as described in this section. The LTE module has to be
up and running for this type of configuration.
The watchdogs‘s I
2
C interface is accessible by means of the LTE module‘s I
2
C lines, and either
via the LTE module‘s AT command interface, or for ELS61T-x Terminals only through a Java
MIDlet during runtime (see
Figure 27 ).
Note:
When using a Java MIDlet to set GPIO directions
using the I
2
C interface, please allow for a guard time of at least 500ms between two I
2
C com-
mands.
The I
2
C interface implements the write and the read protocol as described in Section 8.4.1 . The
7-bit device address is 0x6A (binary: 1101010). The default address can be changed by con-
figuration command (see
Section 8.3.1.10 ).
8.4.1 I
2
C Interface Command Specification
8.4.1.1 WRITE Command Syntax
Example setting the GPIO12 signal direction to “output” (see also section Examples ):
Legend:
S: Start Condition, W: Write bit (=0), A: Acknowledge, P: Stop Condition.
8.4.1.2 READ Command Syntax
Example reading the last status = OK (see also section Examples ):
Legend:
S Slave address
(including write bit “W“)
A Register address A Data byte A P
S 0xD4
(including write bit “0“)
A 0x14 A 0x01 A P
S Slave address
(including read bit “R“)
A Register address A Data length
(only one byte)
N P
S 0xD5
(including read bit “1“)
A 0x00 A 0x01
(only one byte)
N P