User Guide
Table Of Contents
- Document information
- Contents
- 1 LARA-R2 / LARA-R6 modules description
- 2 Migration between LARA modules
- 2.1 Overview
- 2.2 Pin-out comparison between LARA modules
- 2.3 Interfaces comparison between LARA modules
- 2.3.1 VCC module supply input
- 2.3.2 V_INT 1.8 V supply output
- 2.3.3 V_BCKP RTC supply input/output
- 2.3.4 Cellular RF interfaces
- 2.3.5 System control interfaces
- 2.3.6 SIM interface
- 2.3.7 UART interfaces
- 2.3.8 USB interface
- 2.3.9 I2C interface
- 2.3.10 Digital audio interface
- 2.3.11 Clock output
- 2.3.12 GPIOs
- 2.3.13 Antenna dynamic tuning
- 2.3.14 Reserved pins
- 2.3.15 Other considerations and test points
- 2.4 Schematic for LARA modules integration
- Appendix
- A Glossary
- Related documents
- Revision history
- Contact
LARA-R2/R6 migration guide - Application note
UBX-21010015 - R02 Migration between LARA modules Page 17 of 25
C1-Public
supply is applied to the modules: the PWR_ON input line must be properly toggled low, with valid VCC
supply present, to trigger the switch-on sequence of the modules.
The PWR_ON input line can be used to trigger the graceful switch-off procedure of the LARA-R2 and
LARA-R6 series modules, as an alternative to using the +CPWROFF AT command. Afterwards, the
switch-on sequence of modules can be triggered again by properly toggling low PWR_ON input line.
The assertion or toggling of the RESET_N input line causes different actions:
• the RESET_N line of LARA-R2 series modules triggers an unconditional reboot of the module when
toggled, with internal PMU shutdown when set low.
• the RESET_N line of LARA-R6 series modules triggers an unconditional graceful reboot of the
module when set low for a short time period.
• the RESET_N line of LARA-R6 series modules triggers an unconditional shutdown of the module
when set low for a long time period.
The timings for proper control of the PWR_ON and RESET_N input lines of LARA-R2 and LARA-R6
series modules are reported in the related data sheet
[1] and [4].
It is recommended to provide test points on the PWR_ON and RESET_N input lines of LARA-R2 and
LARA-R6 series modules, to trigger the FW update procedure, and for diagnostic purpose.
2.3.6 SIM interface
The same compatible external SIM circuit can be implemented for all LARA modules: external 1.8 V
and 3.0 V SIM card / IC are supported over the available standardized SIM interface (VSIM, SIM_IO,
SIM_CLK, SIM_RST pins).
The same optional SIM detection circuit can be implemented for LARA series modules using the
available GPIO5 pin.
2.3.7 UART interfaces
Main primary UART interface
LARA-R2 and LARA-R6 modules provide a compatible main 8-wire 1.8 V UART interface including:
• data lines (RXD output, TXD input),
• hardware flow control lines (CTS output, RTS input),
• modem status and control lines (DTR input, DSR output, DCD output, RI output)
The main primary UART interface supports AT commands and data communication, multiplexer
functionality including virtual channel for GNSS tunneling, and FW update by means of FOAT on all
the LARA modules.
Additionally, LARA-R2 series modules support the FW update by means of the u-blox EasyFlash tool,
and the diagnostic trace logging functions over the main primary UART interface.
It is recommended to provide test points on RXD and TXD pins of LARA series modules, for FW update
and diagnostic, in particular if the USB interface is connected to the external host processor.
The primary UART interfaces of LARA series modules are electrically compatible, so that the same
compatible external circuit can be used. It is recommended to use the V_INT output to supply the
module side of external voltage translators connected to the UART interfaces.