LARA-R2 series - System Integration Manual
UBX-16010573 - R02
Objective Specification
System description
Page 37 of 148
1.9.1.2
UART AT interface configuration
The UART interface of LARA-R2 series modules is available as AT command interface with the default
configuration described in Table 10 (for more details and information about further settings, see the
u-blox AT
Commands Manual
Interface
AT Settings
Comments
UART interface
AT interface: enabled
AT command interface is enabled by default on the UART physical interface
AT+IPR=0
One-shot autobauding enabled by default on the modules
AT+ICF=3,1
8N1 frame format enabled by default
AT&K3
HW flow control enabled by default
AT&S1
DSR line (Circuit 107 in ITU-T V.24) set ON in data mode
6
and set OFF in command mode
AT&D1
Upon an ON-to-OFF transition of DTR line (Circuit 108/2 in ITU-T V.24), the module (DCE)
enters online command mode
AT&C1
DCD line (Circuit 109 in ITU-T V.24) changes in accordance with the Carrier detect status;
ON if the Carrier is detected, OFF otherwise
MUX protocol: disabled
Multiplexing mode is disabled by default and it can be enabled by AT+CMUX command.
For more details, see the
Mux Implementation Application Note
The following virtual channels are defined:
Channel 0: control channel
Channel 1 – 5: AT commands / data connection
Channel 6: GNSS tunneling
7
Table 10: Default UART AT interface configuration
1.9.1.3
UART signal behavior
At the module switch-on, before the UART interface initialization (as described in the power-on sequence
reported in Figure 13), each pin is first tri-stated and then is set to its related internal reset state
8
. At the end of
the boot sequence, the UART interface is initialized, the module is by default in active-mode, and the UART
interface is enabled as AT commands interface.
The configuration and the behavior of the UART signals after the boot sequence are described below. See
section 1.4 for definition and description of module operating modes referred to in this section.
RXD signal behavior
The module data output line (
RXD
) is set by default to the OFF state (high level) at UART initialization. The
module holds
RXD
in the OFF state until the module does not transmit some data.
TXD signal behavior
The module data input line (
TXD
) is set by default to the OFF state (high level) at UART initialization. The
TXD
line is then held by the module in the OFF state if the line is not activated by the DTE: an active pull-up is enabled
inside the module on the
TXD
input.
6
See the
u-blox AT Commands Manual
[2] for the definition of the command mode, data mode, and online command mode
7
Not supported by “02” product versions
8
Refer to the pin description table in the
LARA-R2 series
