Using Peripherals; Rs-485/422 Port; Can Port - Elatec TWN4 MultiTech Nano Technical Handbook

3. Using Peripherals

3. Using Peripherals
A demo "IO Extender Test" App is available in the Development Pack. Please feel free to use it as a
starting point in order to expedite the development of Your Application. The demo App demonstrates the
use of the peripherals described in this section.

3.1. RS-485/422 Port

Connected to the COM2 port of TWN4 MultiTech Nano Module through a MAX1485CUB Transceiver. The
interface facing the Nano Module operates at 3.3V supply. There are 2 single-ended signals to transmit and
receive data (COM2_TX and COM2_RX) and an active-high TX_Data_Enable (driven by GPIO 4).
The outward-facing Transceiver Interface operates at 5V. This interface can be used in Half-Duplex or Full-
Duplex mode. Use Jumper J3 to switch between the 2 modes. Short the 2 pins closest to the connector
to operate in Full-Duplex mode. Short the 2 pins farthest from the connector to operate in Half-Duplex
mode.
In Full-Duplex mode, use the Bi-Directional port (Y/Z) to transmit data from the Nano Module, and the
Uni-Directional port (A/B) to receive data. In Half-Duplex mode, use the Bi-Directional port (Y/Z) to both
transmit and receive data. Please see Table A.1 for more information.
Both the Bi-Directional and the Uni-Directional ports have optional 120-Ohm on-board terminations. Short
Jumper J4 to enable the termination for the Uni-Directional port. Short Jumper J5 to enable the termination
for the Bi-Directional port.
The maximum Baud Rate supported by the port is 115200. It is up to the User to decide the actual
operating Baud Rate, based on desired cable reach and application requirements.
Please see TWN4 API Reference document for instructions on configuring/using the COM2 port.

3.2. CAN Port

Connected to the CAN port of TWN4 MultiTech Nano Module through a SN65HVD230 Transceiver. The
interface facing the Nano Module operates at 3.3V supply. There are 2 single-ended signals to transmit
and receive data (COM2_TX and COM2_RX).
The SN65HVD230 Transceiver is configured to operate in high-speed mode (Rs pulled to GND) with no
limitation on slew rate.
For the Connector pinout, please see Table A.2.
An on-board termination of 120-Ohm is available by shorting Jumper J6.
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