The RS-485 TX/RX switching is implemented automatically in the Iono’s micro-controller,
based on speed and number of bits detection, and is completely transparent to the
software controlling the UART on Arduino.
The RS-485 line has 620 Ohm pull-up and pull-down resistors on lines A and B. The
biasing resistors ensure that, during idle periods the data lines are kept at a stable voltage
level and prevent false triggering of receiver input. These resistors can be enabled
installing jumpers J4 and J5 respectively.
A 120 Ohm termination resistor between A and B can be enabled installing jumper J3.
RS-485 JUMPERS SCHEMATIC
RS-485 JUMPERS POSITION
Mapping
The following table shows the mapping of the inputs and outputs of the Iono Arduino
module into the related pins of the Arduino platform.
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User Guide
