I’ve been working on a project for a client over the last few months. Like most embedded systems, it needs a simple communications interface for use during manufacturing. The interface is used for such things as testing, calibration, and fine-tuning. For a bunch of embedded systems, the easiest and most cost effective solution is a serial interface. In an effort to reduce cost, all of the level conversion circuitry and the serial connecter were removed from the PCB. Logic level signals needed to interface directly to the system. So, in the factory, a separate dongle is necessary to provide the level conversion. In addition, the vast majority of computers now days no longer have serial ports – they only have USB ports.
Luckily Solutions Cubed has recently come out with a small USB to Serial convertor in our Breakout Module line: the BM010. Taking something off the shelf to use made it very easy to quickly get a convertor up and running for our customer. I simply laid out a PCB to carry the BM010 and the connector to the client’s board. I used the $33 PCB special from Advanced Circuits to get a low cost dongle for our client. The photo below shows the carrier board with the USB to Serial Converter attached; the BM010 is in the lower left corner.
The neat thing about the convertor is that it is based on an FTDI FT232R IC, so the USB drivers downloaded automatically in Windows and I was able to get rolling quickly. The device showed up as a COM port that I was able to access with a Visual Basic program and I could then run the client’s system through its paces. The picture below shows the dongle attached to the target system. I knew that the the break out modules were going to be slick, but even I was impressed by how easy everything came together for the USB to serial converter.