Debug Board

Simple, tiny USB to rs232 converter, also with a galvanic isolation

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I was using a cheap USB serial converter, but sometimes they didn't work correctly and i was losing time.
So we decided to design our own customized board, with only the essential pins. With the galvanic isolation and the possibility to work at different logic level according to the target voltage.

There are two types of debug boards: with and without the galvanic isolation.

The common features are:

  • FTDI FT230X: Compatible with almost all the operating systems and capable of a baud rates of 300 baud to 3 Mbaud
  • TX and RX LEDs indicators
  • Micro USB connector
  • Standard 2.54mm 4 pins female header.
  • Protected by a transparent heat shrink sleeve.


  • TX
  • RX
  • GND
  • VCC

Debug Board with isolation:

The size of this board is just 40 x 13mm. The galvanic isolation is achieved by using the ADUM121N chip, with an isolation up to 400Vrms.

Whit this chip is possible to have the isolation between the target and the PC, plus the voltage level of TX and RX are the same of the target board. This means that it doesn't matter if your board is working at 5V or 3.3V or 1.8V !! the logic level are always correct !

This board can't give the power to the target, but you have to power up.

Debug Board without isolation:

Theis boar is more small respect to the previous one, with a size of 30 x 13mm.

The TX and RX voltage levels are fixed to 3.3V, but can power up your target at 3.3V and with a maximum of 200mA.

We made a small banch of these boards and they are avaiable on Tindie

With isolation:

Witout isolation:

  • New PCB clearence

    fattore.saimon05/29/2017 at 12:45 0 comments

    Unfortunately we discovered a problem with the PCB layout.
    The clearance is not meeting the requirente for the high voltage insulation.
    For this reason we made a new PCB layout with 4mm clarence, enough for isolate up to 1kV

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