SparkFun Satellite Transceiver Kit - Swarm M138 Hookup Guide

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Contributors: Ell C, PaulZC
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Hardware Hookup - Breakout Pins

Want to connect the Breakout to your Arduino microcontroller board? You can absolutely do that too!

By default:

  • The modem TXO breakout pin is connected to the CH340 RXI via a split pad jumper
  • Likewise, the modem RXI is connected to CH340 TXO

You will need to open the jumper links on the back of the board when connecting the TXO and RXI pins to an Arduino board.

Pictured are the T X O and R X I jumpers

You will probably need: break away headers and jumper wires. 2-pin jumpers will be useful for re-linking the CH340 connections later.

Break Away Headers - Straight

Break Away Headers - Straight

PRT-00116
$1.75
20
Jumper Wires Premium 6" M/F Pack of 10

Jumper Wires Premium 6" M/F Pack of 10

PRT-09140
$4.50
1
Break Away Male Headers - Right Angle

Break Away Male Headers - Right Angle

PRT-00553
$2.25
5
Jumper - 2 Pin

Jumper - 2 Pin

PRT-09044
$0.45
Jumper Wires Premium 12" F/F Pack of 10

Jumper Wires Premium 12" F/F Pack of 10

PRT-09389
$4.95
Header - 8-pin Female (PTH, 0.1")

Header - 8-pin Female (PTH, 0.1")

PRT-11895
$0.75

Connect:

  • GND to GND / 0V on your Arduino board
  • VIN to 5V on your Arduino board
    • It is possible to connect VIN to 3.3V if your Arduino board can deliver enough current when the modem transmits
    • Please see Current Draw below for more details.
  • TXO to the Serial / UART RX input on your Arduino board
  • RXI to the Serial / UART TX output on your Arduino board

The TXO and RXI signals are 3.3V.

If you are using an old Arduino Uno or similar with 5V I/O pins, you will need to use a logic level converter to convert the signals to 3.3V.