SARA-R5 series - System integration manual
UBX-19041356 - R04 System description Page 37 of 118
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1.9.1.4 UART multiplexer protocol
SARA-R5 series modules include multiplexer functionality as per 3GPP TS 27.010 [8], on the UART
physical link. This is a data link protocol which uses HDLC-like framing and operates between the
module (DCE) and the application processor (DTE) and allows a number of simultaneous sessions over
the used physical link (UART).
When USIO variant 0 or 1 is set, the following virtual channels are defined (for more details, see the
mux application note [9]):
• Channel 0: control channel
• Channel 1 – 3: AT commands / data communication
• Channel 4: GNSS tunneling
When USIO variant 2 is set, AT commands and data communication are available on second auxiliary
UART, and the following virtual channels are defined on main primary UART (for more details, see the
mux application note [9]):
• Channel 0: control channel
• Channel 1 – 2: AT commands / data communication
• Channel 3: GNSS tunneling
When USIO variant 3 is set, diagnostic trace log is available on second auxiliary UART, and the
following virtual channels are defined on main primary UART (for more details, see the mux application
note [9]):
• Channel 0: control channel
• Channel 1 – 3: AT commands / data communication
• Channel 4: GNSS tunneling
When USIO variant 4 is set, GNSS tunneling is available on second auxiliary UART, and the following
virtual channels are defined on main primary UART (for more details, see the mux application note [9]):
• Channel 0: control channel
• Channel 1 – 3: AT commands / data communication
1.9.2 USB interface
SARA-R5 series modules include a high-speed USB 2.0 compliant interface with a maximum
480 Mbit/s data rate according to the Universal Serial Bus Revision 2.0 specification [4]. The module
itself acts as a USB device and can be connected to any USB host equipped with compatible drivers.
The USB interface is available for diagnostic purpose only.
The USB_D+ / USB_D- lines carry the USB data / signaling, while the VUSB_DET input pin represents
the input to enable the USB interface by applying an external valid USB VBUS voltage (5 V typical).
1.9.3 SPI interfaces
☞ The SPI interface are not supported by the “00” product version of SARA-R5 series modules,
except for diagnostic purpose.
SARA-R5 series modules include 1.8 V Serial Peripheral Interfaces available for communications with
external SPI slave devices, or for diagnostic purpose with the module acting as SPI master.