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SARA-R42 - Application note
UBX-20050829 - R02 Local connectivity Page 14 of 58
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5 Local connectivity
5.1 Serial interface configuration
It is possible to switch between 3 serial interface configuration variants, using the command
+USIO
AT command, as shown in Table 3 .
Command Response Description
AT+USIO=0 OK
(Default configuration)
AT on UART (9-wire: RXD, TXD, CTS, RTS, DTR, DSR, DCD, RI, GND),
trace on USB.
AT+USIO=1 OK AT on UART and AUX UART (5-wire: RX/TX, HW flow control, GND),
trace on USB.
AT+USIO=4 OK AT on UART (5-wire: RX/TX, HW flow control, GND), GNSS tunneling
on AUX UART (5 wire: RX/TX, HW flow ctrl, GND), trace on USB.
Table 3: USIO variants description
☞
Reboot the module to apply the new USIO configuration. For more details on
+USIO
AT command,
see the SARA-R4 series AT commands manual [2] .
☞
AT+USIO=4
option is not supported by SARA-R422 modules.
☞
URCs are sent to both UART and AUX UART interfaces when the
AT+USIO=1
option is set.
☞
It is not possible to have parallel activities on both AT terminals when the double UART
configuration is selected, i.e. in
AT+USIO=1
. The only allowed parallel activity is present when it is
defined a system architecture with a PPP dial-up on one port and AT commands on the other port.
☞
The
+URINGCFG
AT command is not applicable when the
AT+USIO=1
option is selected due to the
fact that the RING line is not available at UART level in this configuration.
5.1.1 Auxiliary (AUX) serial interface configuration
If the AUX UART interface is enabled via the
+USIO
AT command as described above, then it may be
necessary to properly configure this serial interface from the main UART interface, especially for the
first use and in all cases when the factory-programmed configuration does not match the desired
settings.
☞
Configuration changes are stored in the NVM and applied to the AUX UART interface at the next
module boot.
The
+UUARTCONF
AT command applies the desired settings: some examples are reported in Table 4 ;
for additional details, see the SARA-R4 series AT commands manual [2] .
Command Response Description
AT+UUARTCONF=1,115200,3 OK
Set the desired baud rate and flow control mode for
the auxiliary UART interface.
AT+UUARTCONF? +UUARTCONF: 0,115200,3
+UUARTCONF: 1,115200,3
OK Check the current settings for both the main UART
and the auxiliary UART interfaces.
AT+UUARTCONF=? +UUARTCONF: 1,(300,600,1200
,2400,4800,9600,14400,19200
,38400,57600,115200,230400,
460800,921600,1000000,12000
00,1500000,2000000,3000000)
,(0-3)
OK Visualize the possible settings to be applied in the
auxiliary UART handling.
Table 4: +UUARTCONF variants description