Integration Manual

LISA-U series - System Integration Manual
3G.G2-HW-10002-A3 Preliminary System description
Page 53 of 160
In case of multiple events (incoming call plus SMS received), the RI line can’t be used to discriminate the
two events, but the DTE must rely on the subsequent URCs and interrogate the DCE with the proper
commands.
1.9.2.3 UART and power-saving
The power saving configuration is controlled by the AT+UPSV command (for the complete description please
refer to u-blox AT Commands Manual [3], AT+UPSV command). When power saving is enabled, the module
automatically enters idle-mode whenever possible, otherwise the active-mode is maintained by the module. The
AT+UPSV command sets the module power saving configuration, but also configures the UART behavior in
relation to the power saving configuration. The conditions for the module entering idle-mode also depend on
the UART power saving configuration.
The different power saving configurations that can be set by the AT+UPSV command are described in the
following subchapters and are summarized in Table 24. For more details on the command description please
refer to u-blox AT commands Manual [3].
AT+UPSV
HW flow control
RTS line
Communication during idle-mode and wake up
0
Enabled (AT&K3)
ON
Data sent by the DTE will be correctly received by the module.
0
Enabled (AT&K3)
OFF
Data sent by the module will be buffered by the module and will be correctly received by
the DTE when it will be ready to receive data (i.e. RTS line will be ON).
0
Disabled (AT&K0)
ON
Data sent by the DTE will be correctly received by the module.
0
Disabled (AT&K0)
OFF
Data sent by the module will be correctly received by the DTE if it is ready to receive data,
otherwise data will be lost.
1
Enabled (AT&K3)
ON
Data sent by the DTE will be buffered by the DTE and will be correctly received by the
module when active-mode is entered.
1
Enabled (AT&K3)
OFF
Data sent by the module will be buffered by the module and will be correctly received by
the DTE when it is ready to receive data (i.e. RTS line will be ON).
1
Disabled (AT&K0)
ON
If the module is in idle-mode, when a low-to-high transition occurs on the TxD input line,
the module switches from idle-mode to active-mode after 20 ms: this is the “wake up time”
of the module. As a consequence, the first character sent when the module is in idle-mode
(i.e. the wake up character) won’t be a valid communication character because it can’t be
recognized, and the recognition of the subsequent characters is guaranteed only after the
complete wake-up (i.e. after 20 ms).
1
Disabled (AT&K0)
OFF
Data sent by the module will be correctly received by the DTE if it is ready to receive data,
otherwise data will be lost.
2
Enabled (AT&K3)
ON
Not Applicable: HW flow control cannot be enabled with AT+UPSV=2.
2
Enabled (AT&K3)
OFF
Not Applicable: HW flow control cannot be enabled with AT+UPSV=2.
2
Disabled (AT&K0)
ON
The module is forced in active-mode and it can’t enter idle-mode until RTS line is set to OFF
state. When a high-to-low (i.e. OFF-to-ON) transition occurs on the RTS input line, the
module switches from idle-mode to active-mode after 20 ms: this is the “wake up time” of
the module.
2
Disabled (AT&K0)
OFF
When a low-to-high transition occurs on the TxD input line, the UART is re-enabled and if
the module was in idle-mode it switches from idle-mode to active-mode after 20 ms: this is
the “wake up time” of the module. As a consequence, the first character sent when the
module is in idle-mode (i.e. the wake up character) won’t be a valid communication
character because it can’t be recognized, and the recognition of the subsequent characters
is guaranteed only after the complete wake-up (i.e. after 20 ms).
Table 24: UART and power-saving summary
AT+UPSV=0: power saving disabled, fixed active-mode
The module doesn’t enter idle-mode and the UART interface is enabled (data can be sent and received): the CTS
line is always held in the ON state after UART initialization. This is the default configuration.