USB Adapter Rejuvenates IEEE-488 Instruments

If you think the time has passed for older instruments with only an IEEE-488-bus interface, or GPIB connection, think again.  You can put together a simple bus converter for under $100. Commercial USB-to-GPIB adapter start at about $US 500, so I’d build my own. It’s easier than you think.

The April 2011 issue of elektor magazine (www.elektor.com) includes a five-page article that describes how the author used a Prolific PL2303 USB-to-serial “bridge” controller and a Renesas R8C/13 16-bit microcontroller to build his own bus converter. If you don’t subscribe to elektor, you can buy the April 2011 issue for $US 7.80.  The bus converter takes advantage of a ready-to-use board sold through the elektor Web site. This board provides the PL2303 and R8C/13 MCU. You add the microcontroller code–available for free–and an IEEE-488 cable and connector.

The author of an earlier project created the small MCU circuit board for a curve-tracer project, but because it provides 18 uncommitted digital I/O pins and a USB interface, it easily adapted to the IEEE-488-bus-converter project. The assembled board costs $US 88 (part no. 080068-91 on the elektor Web site). An arrow in the image below points to the MCU-USB board as it attaches to the curve-tracer circuit, which you don’t use in this project. (Photo courtesy of elektor magazine.)

For more information about this project, visit: http://www.elektor.com/100756. The information on this page shows an “unpopulated” circuit board, but the board from elektor comes with all components, less the IEEE-488 cable, soldered in and ready to go. The author, Rainer Schuster, wrote the C-language firmware with the Renesas High-performance Embedded Workshop (HEW, ver 4.08).  Learn more about this free software-development tool at: http://www.renesas.com/products/tools/ide/ide_hew/ide_hew_tools_product_landing.jsp.

The article notes you also will need the Renesas “Flash Development Toolkit 3.4 Basic” and it provides two links, but I could not locate this software in either place. The software takes the compiled code created in the HEW and downloads it into a variety of Renesas MCUs. I did locate later versions of the Flash toolkit at: http://www.renesas.com/products/tools/flash_prom_programming/fdt/download_search_results.jsp.  I recommend you use the latest version of this toolkit and the HEW software. You also might like a regular subscription to elektor magazine.–Jon Titus