User's Guide

LE910Cx Hardware User Guide

1VV0301298 Rev. 1.01 - 2016-02-16

Telit Confidential Information, provided under NDA Page 71 of 114

NOTE:

For minimum implementations, only the TXD and RXD lines need be connected. The other lines

can be left open provided a software flow control is implemented.

NOTE:

According to V.24, Rx/Tx signal names refer to the application side; therefore, on the LE910Cx side,

these signal are in the opposite direction: TXD on the application side will be connected to the

receive line (here named TXD/ RX_UART) of the LE910Cx serial port and vice versa for Rx.

8.4.2. Modem Serial Port 2

Serial Port 2 on the LE910Cx is a +1.8V UART with RX and TX signals only.

The UART functionality is shared with SPI thus simultaneous of SPI and UART is not supported.

The below table lists the signals of LE910Cx Serial Port 2.

Table 25 Modem Serial Port 2 Signals

PAD

Signal

I/O

Function

Type

COMMENT

D15

TX_AUX

Auxiliary UART (Tx Data to DTE)

1.8V

Shared with SPI_MOSI

E15

RX_AUX

Auxiliary UART (Rx Data to DTE)

1.8V

Shared with SPI_MISO

NOTE:

To avoid a back-powering effect, it is recommended to avoid having any HIGH logic level signal

applied to the digital pins of the module when it is powered OFF or during an ON/OFF transition.

NOTE:

The Auxiliary UART is used as the SW main debug console. It is required to place test points on this

interface even if not used.