User's Manual

TOBY-R2 series - System Integration Manual

UBX-16010572 - R04 System description

Page 37 of 147

1.9 Data communication interfaces

TOBY-R2 series modules provide the following serial communication interface:

 UART interface: Universal Asynchronous Receiver/Transmitter serial interface available for the communication

with a host application processor (AT commands, data communication, FW update by means of FOAT), for

FW update by means of the u-blox EasyFlash tool and for diagnostic. (see section 1.9.1)

 USB interface: Universal Serial Bus 2.0 compliant interface available for the communication with a host

application processor (AT commands, data communication, FW update by means of the FOAT feature), for

FW update by means of the u-blox EasyFlash tool and for diagnostic. (see section 1.9.2)

 DDC interface: I

C bus compatible interface available for the communication with u-blox GNSS positioning

chips or modules and with external I

C devices as an audio codec. (see section 1.9.3)

 SDIO interface: Secure Digital Input Output interface available for the communication with compatible

u-blox short range radio communication Wi-Fi modules. (see section 1.9.4)

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 TOBY-R2 series

modules, supporting:

 AT command mode

 Data mode and Online command mode

 Multiplexer protocol functionality (see 1.9.1.5)

 FW upgrades by means of the FOAT feature (see 1.14.13 and Firmware Update Application Note [5])

 FW upgrades by means of the u-blox EasyFlash tool (see Firmware Update Application Note [5])

 Trace log capture (diagnostic purpose)

UART interface provides RS-232 functionality conforming to the ITU-T V.24 Recommendation [7], 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 detailed

electrical characteristics see TOBY-R2 series Data Sheet [1]), 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).

TOBY-R2 series modules are designed to operate as cellular modems, i.e. as the data circuit-terminating

equipment (DCE) according to the ITU-T V.24 Recommendation [7]. A host application processor connected to

the module through the UART interface represents the data terminal equipment (DTE).

UART signal names of the cellular modules conform to the ITU-T V.24 Recommendation [7]: e.g. TXD line

represents data transmitted by the DTE (host processor output) and received by the DCE (module input).

TOBY-R2 series modules’ UART interface is by default configured in AT command mode: the module waits for

AT command instructions and interprets all the characters received as commands to execute. All the

functionalities supported by TOBY-R2 series modules can be in general set and configured by AT commands:

 AT commands according to 3GPP TS 27.007 [8], 3GPP TS 27.005 [9], 3GPP TS 27.010 [10]

 u-blox AT commands (for the complete list and syntax see the u-blox AT Commands Manual [2])

For the definition of the interface data mode, command mode and online command mode see the u-blox AT Commands Manual [2]