Connecting the USB-UART cable to the PICO-DWARF, PICO-HOBBIT, and PICO-NYMPH baseboards

Difficulty Levels: Intermediate
Date added: March 19, 2018

This tutorial provides instructions for how to connect our USB-UART adapter cable (TechNexion Part Number: USBUART330TTLFTDI100) to our PICO-DWARF, PICO-HOBBIT, and PICO-NYMPH baseboards.

TechNexion FTDI-based USB Type A to UART (3.3V TTL) cable
Part Number:


The USB-UART cable is primarily used to provide a serial console for the purposes of programming, configuration, and debugging. It provides a simple connection to UART signal pins at 3.3V levels and makes the serial port available via a USB Type A connection to a host computer. The host computer provides power to the cable’s built-in USB-UART chip.

Connecting the cable to the board

On one end of the cable is a pin header that is connects directly into the CON1 connector site on the Dwarf baseboard using compression-fitting pins.

PICO-DWARF with USB serial cable connected
PICO-DWARF with USB serial cable connected
PICO-NYMPH with USB serial cable connected
PICO-HOBBIT with USB serial cable connected

Note the black wire (GND) connects to pin 1. Making sure that the board is powered off, insert the pins carefully to ensure that all of the pins seat into the holes, and press firmly to fully push the pins through the holes. This may take more force the first time. It will stay plugged in until forcibly removed.

After the cable is plugged into the board, connect the other end of the cable (the USB Type A connector) into a port on your host computer and use your preferred serial terminal emulator application such as screen, minicom, and PuTTY on Linux and MacOS, and Hyperterm or Teraterm on Windows.

The default baud rate for the serial console on our products is 115200 baud, 8 bits, no parity, and 1 stop bit, with no hardware flow control (115200,8,N,1).

DWARF CON1 Connector Site

The following picture is a section of the Dwarf schematic showing CON1.  The important connections are GND (pin 1), UART transmit (pin 2), and UART receive (pin 4).

USB-UART Cable-to-Board Connector

USB-UART cable-to-board connector and signals

1 GND (Black)
2 RX (Device -> Host)
3 3.3V (Not used)
4 TX (Host -> Device)
5 Not Used
6 Not Used

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