Connecting the development cable

[Kalin Nakov]

Developing on the Raspberry Pi is slow, because the CPU it has it slow and can't run a whole Eclipse IDE for example, compile fast and debug the source code. Attaching a monitor, cable and development environment there is too much for the Raspberry Pi. That's why we found out that it's a lot easier to replace the Raspberry Pi with the desktop PC or laptop during the software development. The cable you have connects the Vehicle Pi shield to the PC's USB port. Then, the Vehicle Pi appears as a peripheral device connected over the serial port to the PC. Then you can launch Eclipse (or your favorite IDE), load your project and debug your software based on the SDK. 

The intended development process is to have several Vehicle Pis connected with the USB cables to developer PCs for software development and when the software release is complete to push the resulting JAR file to the buses/trucks/cars via OTA upgrade (or manually on the SD card). This means the Raspberry Pi computer is not needed for development but only for running the application inside the vehicle. To make the development process even easier, we're working on a special hardware board, called "Vehicle Pi development kit", which will replace the USB cable when ready. The development kit will have 3 important features that the USB cable can't provide - J1939 simulator socket, LEDs and buttons for the GPIO and power supply. Read the ** notes at the end of the document for more information on the power supply issues.

To connect the cable, you need to dismount the sandwich. Find the white screws and detach the two boards and put the Raspberry Pi computer aside (you don't need it for this setup). Then put the Vehicle Pi board with the black rectangle that was previously attached to the Raspberry Pi facing up. Then get the cable (if you have the older cable with the full 2x5 male pins plug it in the black socket with the label "TO LEDS" facing towards the 3 LEDs). 

If you have the newer cable that has only 4 pins, plug it like this (the single pin points to the LEDs). This is documented in the SDK.

** Power issues. When you plug in the USB cable and the Vehicle Pi will power up. The power though will not be enough for the GSM and the ECU connectivity. If you have a protocol simulator on your desktop or want to use the GSM, please provide a steady 12V/24V power supply to the main plug (the white 12 pin plug). If you attach a lot of USB peripherals like monitors, keyboards, etc, make sure you provide 5V USB power supply to the Raspberry Pi too.