Installation Instructions

LISA-U2 series - System Integration Manual
UBX-13001118 - R19 Early Production Information System description
Page 66 of 175
Figure 30 shows the case where in addition to the wake-up character further (valid) characters are sent. The
wake up character wakes-up the module UART. The other characters must be sent after the “wake up time” of
~20 ms. If this condition is satisfied, the module (DCE) recognizes characters. The module will disable the UART
after 2000 GSM frames from the latest data reception.
The “wake-up via data reception” feature cannot be disabled.
In command mode
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, if autobauding is enabled and the DTE does not implement HW flow control, the DTE
must always send a character to the module before the “AT” prefix set at the beginning of each
command line: the first character is ignored if the module is in active-mode, or it represents the wake-up
character if the module is in idle-mode.
In command mode
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, if autobauding is disabled, the DTE must always send a dummy “AT” before each
command line: the first character is not ignored if the module is in active-mode (i.e. the module replies
“OK”), or it represents the wake up character if the module is in low power idle-mode (i.e. the module
does not reply).
No wake-up character or dummy “AT” is required from the DTE during a voice or data call since the
module UART interface continues to be enabled and does not need to be woken-up. Furthermore in data
mode
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a dummy “AT” would affect the data communication.
Additional considerations
The LISA-U2 series modules are forced to stay in active-mode if the USB is connected and not suspended, and
therefore the AT+UPSV=1, AT+UPSV=2 or AT+UPSV=3 settings are overruled but they have effect on the UART
behavior: they configure UART interface power saving, so that UART is enabled / disabled according to the
AT+UPSV=1, AT+UPSV=2 or AT+UPSV=3 settings.
To set the AT+UPSV=1, AT+UPSV=2 or AT+UPSV=3 configuration over the USB interface of LISA-U2 modules,
the autobauding must be previously disabled on the UART by the +IPR AT command over the used AT interface
(the USB), and this +IPR AT command configuration must be saved in the module’ non-volatile memory (see
u-blox AT Commands Manual [2]). Then, after the subsequent module re-boot, AT+UPSV=1, AT+UPSV=2 or
AT+UPSV=3 can be issued over the used AT interface (the USB): all the AT profiles are updated accordingly.
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Refer to the u-blox AT Commands Manual [2] for the definition of the interface data mode, command mode and online command mode.