SARA-R4/N4 series - System Integration Manual
UBX-16029218 - R11
System description
Page 38 of 157
1.9
Data communication interfaces
SARA-R4/N4 series modules provide the following serial communication interface:
USB interface: Universal Serial Bus 2.0 compliant interface available for the communication with a host
application processor (AT commands, data, FW update by means of the FOAT feature), for FW update
by means of the u-blox dedicated tool and for diagnostics. See section
SPI interface: Serial Peripheral Interface available for communication with an external compatible device.
See section
SDIO interface: Secure Digital Input Output interface available for communication with a compatible
device. See section
DDC interface: I
2
C bus compatible interface available for the communication with u-blox GNSS
positioning chips or modules and with external I
2
C devices. See section
1.9.1
UART interface
1.9.1.1
UART features
The UART interface is a 9-wire 1.8 V unbalanced asynchronous serial interface available on all the SARA-
R4/N4 series modules, supporting:
AT command mode
7
Data mode and Online command mode
Multiplexer protocol functionality
FW upgrades by means of the FOAT feature (see
☞
The UART is available only if the USB is not enabled as AT command / data communication interface:
UART and USB cannot be concurrently used for this purpose.
UART interface provides RS-232 functionality conforming to the ITU-T V.24 Recommendation
, with CMOS
compatible signal levels: 0 V for low data bit or ON state, and 1.8 V for high data bit or OFF state (for
electrical characteristics see the SARA-R4/N4 series Data Sheet
), providing:
data lines (
RXD
as output,
TXD
as input)
hardware flow control lines (
CTS
as output,
RTS
as input)
modem status and control lines (
DTR
as input,
DSR
as output,
DCD
as output,
RI
as output)
7
For the definition of the interface data mode, command mode and online command mode see SARA-R4/N4 series AT Commands Manual
