Integration Manual

LISA-U2 series - System Integration Manual
UBX-13001118 - R25 System description Page 67 of 182
☞ 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 communications.
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 still have effect on the UART behavior: they configure the UART interface power saving, so that
the 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’s non-volatile memory (see the 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.