Fiat Coupe to USB adaptor
The Coupe to USB adaptor - AKA 'microwidget' is an inline adaptor to allow a laptop user running Windows 2k or Windows XP (it is as yet untested with Vista but should work) to interrogate the ECU on the Fiat Coupe. With suitable software, the ECU can be interrogated to obtain running data (intake pressure, temperatures, throttle position etc), any current or stored error information, or commanded to perform hardware tests or to clear fault codes.
The microwidget should act as a generic K-L line to USB line converter: the USB serial chip appears to be able to handle any Windows baud rate above 300 baud where the outgoing line is the L line and the incoming K line. A link is provided so that systems where everything happens on the K line (e.g. the Fiat Coupe 20v/vt) can be communicated with.
Windows Drivers
It's important that the correct drivers are installed on the PC before the microwidget is plugged in, or Windows will install default drivers.
The latest drivers are available from the chip manufacturer, FTDI, here: FTDI driver page. It is important that the FTDI installation instructions are followed; the system should load two drivers rather than one which might be expected.
Star Trek software
The Star Trek software is a *very* rough and ready application that can use the USB microwidget (or earlier serial versions) to display running sensor and engine values and current error messages for the Fiat Coupe 16v NA and 16vt only. It will also work with other engines in the Fiat/Alfa/Lancia range which use the same ECU. It will not at present work for the Coupe 20v/vt Bosch ECU nor with the Hitachi ECU used in the 1800 16v.
The code, such as it is, is released under the LGPL licence. The executable can be downloaded here: Star Trek executable.
This: Zipped package. contains zips of two variants of the circuit - one for USB as illustrated above and one RS232 serial - as well as circuit board layouts. You'll need the Eagle CAD software to view them; it's free.
If you try and run the code without any serial ports - as many modern laptops - it will politely decline. Only available serial ports are listed in the drop-down box - choose your preferred port there. Insert the microwidget and try again. The program waits for you to select an engine variant before it starts polling the ECU - please note that the 20v and 20vt options are stubs for later expansion.