LISA-U2 series - System integration manual
UBX-13001118 - R27
System description
Page 59 of 183
C1-Public
If AT+UPSV=2 is set and HW flow control is disabled, the
RTS
line is monitored by the module to
manage the power saving configuration:
•
When an OFF-to-ON transition occurs on the
RTS
input line, the UART is enabled and the module
is forced to active mode: after 20 ms from the transition the switch is completed and data can be
received without loss. The module cannot enter idle mode and the UART is kept enabled as long
as the
RTS
input line is held in the ON state
•
If
RTS
is set to OFF state by the DTE, the UART is immediately disabled (held in low-power mode)
and the module automatically enters idle mode whenever possible
For more details on the power saving configuration controlled by the
RTS
input line see section
and the u-blox AT commands manual
, AT+UPSV command.
DSR signal behavior
If AT&S0 is set, the
DSR
module output line is set by default to ON state (low level) at UART
initialization and is then always held in the ON state.
If AT&S1 is set, the
DSR
module output line is set by default to OFF state (high level) at UART
initialization. The
DSR
line is then set to the OFF state when the module is in command mode or in
online command mode and is set to the ON state when the module is in data mode (see the u-blox AT
commands manual
for the definition of the interface data mode, command mode and online
command mode).
☞
The above behavior is valid for both Packet-Switched and Circuit-Switched data transfers.
DTR signal behavior
The
DTR
module input line is set by default to OFF state (high level) at UART initialization. The
DTR
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
DTR
input. Module behavior according to
DTR
status depends
on the AT command configuration (see the u-blox AT commands manual
, &D AT command).
Except for “01” product version, if AT+UPSV=3 is set, the
DTR
line is monitored by the module to
manage the power saving configuration:
•
When an OFF-to-ON transition occurs on the
DTR
input line, the UART is enabled and the module
is forced to active mode: after 20 ms from the transition, the switch is completed and data can be
received without loss. The module cannot enter idle mode and the UART is keep enabled as long
as the
DTR
input line is held in the ON state
•
If
DTR
is set to OFF state by the DTE, the UART is immediately disabled (held in low-power mode)
and the module automatically enters idle mode whenever possible
For more details on the power saving configuration controlled by the
DTR
input line, see section
and the u-blox AT commands manual
, AT+UPSV command.
DCD signal behavior
If AT&C0 is set, the
DCD
module output line is set by default to ON state (low level) at UART
initialization and is then always held in the ON state.
If AT&C1 is set, the
DCD
module output line is set by default to OFF state (high level) at UART
initialization. The
DCD
line is then set by the module in accordance with the carrier detect status: ON
if the carrier is detected, OFF otherwise. For a voice call,
DCD
is set to ON state when the call is
established. For a data call there are the following scenarios (see the u-blox AT commands manual
for the definition of the interface data mode, command mode and online command mode):
•
PSD data call
: Before activating the PPP protocol (data mode) a dial-up application must provide
the ATD*99***<context_number># to the module: with this command the module switches from
command mode to data mode and can accept PPP packets. The module sets the
DCD
line to the
