User's Manual

LE910 V2 HARDWARE USER GUIDE 1VV0301200 Rev.2 Preliminary • 2015-08-04 44 of 81
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NOTE:
According to V.24, some signal names are referred to the application side, therefore on
the LE910 V2 side these signal are on the opposite direction:
TXD on the application side will be connected to the receive line (here named C103/TXD)
RXD on the application side will be connected to the transmit line (here named
C104/RXD)
For a minimum implementation, only the TXD, RXD lines can be connected, the other
lines can be left open provided a software flow control is implemented.
In order to avoid a back powering effect it is recommended to avoid having any HIGH
logic level signal applied to the digital pins of the LE910 V2 when the module is powered
off or during an ON/OFF transition.
5.5.3.2 Modem serial port 2 (USIF1)
The secondary serial port on the LE910 V2 is a CMOS1.8V with only the RX and TX signals.
The signals of the LE910 V2 serial port are:
PAD
Signal
I/O
Function
Type
NOTE
D15
TX_AUX
O
Auxiliary UART (TX Data to
DTE)
CMOS 1.8V
Shared with SPI_MOSI
E15
RX_AUX
I
Auxiliary UART (RX Data
from DTE)
CMOS 1.8V
Shared with SPI_MISO
NOTE:
Due to the shared pins, when the Modem Serial port is used, it is not possible to use the
SPI functions.
In order to avoid a back powering effect it is recommended to avoid having any HIGH
logic level signal applied to the digital pins of the LE910 V2 when the module is powered
off or during an ON/OFF transition.