Tools – Isolated USB to UART

Connecting an embedded systems UART to a PC through a USB to UART converter is something that every embedded software developer is familiar with.  Many developers don’t leave home without a FTDI232R board from Sparkfun (  The only problem with this great little tool though is that it doesn’t provide any protection to the PC in the event that something goes terribly wrong with the embedded system and vice-versa.


There are a number of different ways that a developer can add isolation to the standard break-out board; however, there are also a number of other low cost break-out boards that do provide protection for the PC and embedded system.  One option is a board from Saurus Electornics located at and runs for around $15 euros.  This board has added opto-isolators to the FTDI232.  One down-side of adding isolation is that the 3 Mbps will most like be unattainable.  The limits seem to be around 1 Mbps which should still be good enough for most applications.

Where the isolated USB to UART comes from really doesn’t matter.  What is important is that the PC and embedded system are protected from any mishaps and are capable of at least a baud rate of 1 Mbps.  The Saurus board is one example of a low cost solution.  There are other more robust and professionally housed solutions such as those from B&B.  Just remember that the project goes much smoother when the right tools are available and protected from accidental mishaps!

(Next month I will give an example of how to build your own low cost isolated USB->Uart board).


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