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2.1.6 FS Mode
The Frequency Synthesis (FS) mode is an intermediate mode between the standby mode and the RX or TX modes, where
the PLL and the associated regulators are switched on. BUSY goes low as soon as the PLL is locked.
2.1.7 GNSS Scanning Mode
The GNSS scanning mode allows to detect GPS and BeiDou signals on the RFI_N_LF1 and RFI_P_LF1 pins for outdoor
geolocation. The satellite data is then extracted and processed by the integrated DSP. At the end of the satellite data
processing, the BUSY signal returns to low, indicating that the GNSS scanning data is available to the host controller. The
processing result can then be transmitted to a geolocation server using a LPWAN network to compute the device position.
Different GNSS scanning sub-modes are available, depending on the availability of almanac data and assistance
information. Refer to the section
2.1.8 Wi-Fi Passive Scanning Mode
The Wi-Fi Passive Scanning mode allows the detection of Wi-Fi signals (802.11b, g, or n) from access points in the proximity
of the device on the RFIO_HF pin. The Wi-Fi signal is processed by the integrated DSP, and the available MAC Addresses are
extracted. At the end of the Wi-Fi signal processing, the BUSY signal returns to low, indicating that the MAC addresses are
available to the host controller and ready to be sent to a geolocation server using a LPWAN network to compute the device
position.
2.1.9 DSP Mode
LR1110 geolocation functions require processing of the Wi-Fi or GNSS environment captures. In this mode, only the DSP
and the associated regulators are kept active in order to minimize the power consumption.
2.2 Startup Sequence
At power-up or after a reset, the device initiates its startup phase. The BUSY pin is set to high, indicating that the device is
busy and cannot accept a command. When the power management unit and the RC oscillator become available, the
embedded CPU starts and executes the internal firmware. At the end of the startup sequence, the device is set in Standby
RC mode, the BUSY signal goes down and the device is ready to accept commands.
2.3 Reset
Three reset sources are available to trigger a LR1110 restart, executing the startup sequence: Power-On-Reset / Brown-Out
Reset (POR/BRN), NRESET, and Reboot( ) command.
The BUSY signal is kept high during each one of the reset procedures, and returns to low when the restart procedure is
finished, and when the device is ready to accept commands. At the end of the restart procedure, the device goes into
Standby mode with RC oscillator on. The whole device context is lost during this operation, and the device shall be
re-configured. The calibrations shall also be re-launched.
POR/BRN and NRESET also trigger an authentication of the internal firmware. The transition time to STBY_RC is then
approximately 180 ms.
LR1110
User Manual
Rev.1.0
UM.LR1110.W.APP
March 2020
11. GNSS Scanning
for more details.
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