Integration Manual

TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R04 Advance Information System description
Page 43 of 141
1.9.2.3 UART signals behavior
At the module switch-on, before the UART interface initialization (as described in the power-on sequence
reported in Figure 14), each pin is first tri-stated and then is set to its relative internal reset state. 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.
1.9.2.4 UART and power-saving
The power saving configuration is controlled by the AT+UPSV command (for the complete description, see the
u-blox AT Commands Manual [3]). When power saving is enabled, the module automatically enters low power
idle-mode whenever possible, and otherwise the active-mode is maintained by the module (see section 1.4 for
definition and description of module operating modes referred to in this section).
The AT+UPSV command configures both the module power saving and also the UART behavior in relation to the
power saving. The conditions for the module entering low power idle-mode also depend on the UART power
saving configuration, as the module does not enter the low power idle-mode according to any required activity
related to the network (within or outside an active call) or any other required concurrent activity related to the
functions and interfaces of the module, including the UART interface.
1.9.2.5 UART multiplexer protocol
TOBY-L2 series modules have a software layer with multiplexer functionality as per 3GPP TS 27.010 Multiplexer
Protocol [10], available on the UART physical link.
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 (the UART interface): the user can concurrently use AT command interface on one MUX channel
and data communication on another multiplexer channel.
The following virtual channels are defined:
 Channel 0: control channel
 Channel 1 – 5: AT commands / data connection
 Channel 6: GNSS tunneling
 Channel 7: SIM Access Profile
For more details, see Mux implementation Application Note [11].