The connection between the PDA and the Buell ECM is created via special cable and dongle (connector).
So far, ECMSpy is only supported on PalmOS for PDA. Many different connector adaptors and cables are provided to connect to the PDA. Additionally, the Palm PDA provides different serial interface connectors; some work with the standard RS232 interface (known from PCs), others support the TTL interface, as it is known in the world of microcontrollers and electronics.
The ECM requires signal currents of between 0 and 5 Volts, which falls into the voltage range of TTL interfaces. A PDA with RS232 interface (-12 Volt to +12 Volt) requires a voltage converter which adjusts the signal currents to the ones requires by the ECM (TTL level, as mentioned above).
When no user input is detected, It is quite common for PDA to power-off automaticaly after a given amount of time, to conserve battery life. On some PDA this feature can be turned off when the device is connected to an external power supply. The serial voltage converter (RS232 to TTL) requires an external power supply as well, which can also be used to supply the PDA at the same time. PIN 4, on the Diagnostics Connector of the Buell ECM provides a handy supply of on average 12 Volts. This can be used as power source for the serial voltage converter as well as supplying the PDA at the same time.
Only a handful of components are needed for the Converter and Supply electronics, which can be easily obtained from electronics suppliers such as Maplins and RS Components (both in the UK). The grouping-together and building of these components can also be placed on a pre-drilled assembly board, equally available from the aforementioned companies. If you require a smaller form factor unit then you will need to create (etch) your own cicuit board.
A very simple layout of the electronics needed to connect to the ECM would look as follows (click on the image to see a bigger version in a new window):
The top half of the image concerns the voltage supply to the PDA and the serial voltabe converter, the lower half the serial voltage converter itself. The connector layout for the four clips is as follows:
The bill of materials needed for the diagram above is not particularly long:
To connect to the ECM's diagnostics port a additional connector is required. This connector can be obtained from a company called Deutsch IPD, part number "DT 06-4S". Only three of the four connections in the ECM's diagnostic port are active. Transmit, PIN 3, Receive, PIN 1 and Ground, PIN 2. The numbers are engraved on the back of the Deutsch connector.
Thanks to Michel for translation.