Ublox SARA-G300 - Auxiliary Asynchronous Serial Interface (AUX UART)

SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R26 System description
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1.9.1.5 Multiplexer protocol (3GPP TS 27.010)
SARA-G3 and SARA-U2 series modules have a software layer with MUX functionality, the 3GPP TS 27.010
Multiplexer Protocol [13], available on the UART physical link. The auxiliary UART, the USB and the DDC (I
2
C)
serial interfaces do not support the multiplexer protocol.
This is a data link protocol (layer 2 of OSI model) which uses HDLC-like framing and operates between the
module (DCE) and the application processor (DTE) and allows a number of simultaneous sessions over the used
physical link (UART or SPI): the user can concurrently use AT command interface on one MUX channel and
Packet-Switched / Circuit-Switched Data communication on another multiplexer channel. Each session consists of
a stream of bytes transferring various kinds of data such as SMS, CBS, PSD, GNSS, AT commands in general. This
permits, for example, SMS to be transferred to the DTE when a data connection is in progress.
The following virtual channels are defined:
 Channel 0: control channel
 Channel 1: AT and data
 Channel 2: AT and data
 Channel 3: AT and data (not available on SARA-G300 / SARA-G310 modules)
 Channel 4: AT and data (not available on SARA-G300 / SARA-G310 modules)
 Channel 5: AT and data (not available on SARA-G300 / SARA-G310 modules)
 Channel 6: GNSS tunneling (not available on SARA-G300 / SARA-G310 modules)
 Channel 7: SIM Access Profile (not available on SARA-G3 series modules)
For more details, see the Mux implementation Application Note [25].
1.9.2 Auxiliary asynchronous serial interface (AUX UART)
The auxiliary UART interface is not available on SARA-U2 “00”, “03”, “53”, “63”, “73” product versions.
The auxiliary UART interface is a 3-wire 1.8 V unbalanced asynchronous serial interface available over:
 RXD_AUX data output pin and TXD_AUX data input pin on SARA-G3 modules
 SCL pin configured as RXD_AUX output and SDA pin configured as TXD_AUX input on SARA-U2 modules
The auxiliary UART interface supports:
 AT command mode
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 GNSS tunneling mode
 FW upgrades by means of the u-blox EasyFlash tool (see the Firmware update application note [27])
 Trace log capture (diagnostic purposes)
SARA-G3 series modules product versions “00” and “01” do not support the AT command mode and the
GNSS tunneling mode over the Auxiliary UART interface.
SARA-U2 series modules do not support the GNSS tunneling and FW upgrades by means of the u-blox
EasyFlash tool over the Auxiliary UART interface.
SARA-G3 and SARA-U2 series modules do not support the Data mode and Online command mode
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over
the Auxiliary UART interface.
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See the u-blox AT Commands Manual [3] for the definition of the command mode, data mode, and online command mode.