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Currently a standard DC jack 5.5\/21.mm is connected to the the LIN-interface voor the power supply and the blue LIN bus wire connects to an available LIN bus spade connector behind the campervan-side batteries of the Nugget. The ESP32 is powered through a USB cable. Eventually when making a more permanent design it can powered form the car battery side with an additional DC\/DC convertor.<\/p>\n\n\n\n
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As Software Development Environment I use Visual Studio Code and the PlatformIO plugins. Within PlatformIO I make use of the Arduino framework for ESP32 and installed the ESP32 and Heltec libraries. The latter for OLED support. The code will eventually end up at github.\u00a0<\/p>\n
An introduction to coding and programming the ESP32 is beyond the scope of this post. Many good tutorials can be found, for example those:<\/p>\n
PlatformIO tutorials<\/a> or\u00a0Random Nerds Tutorials<\/a><\/p>\n To interface with the LIN bus I forked two repositories of Mestrode<\/a>. The first is a library to drive the dedicated functions of the TJA1021, and the second is the generic implementation of the LIN bus protocol using a serial interface of the ESP32. Both I had to fork as I needed to extend them. The transceiver library was using hard-coded TX\/RX pins and for the Heltec board those pins were occupied by other functions. And for the interface library there was no spy-mode reading function implemented. I need to listen-only to the bus, while it is not in sleep mode. A new frame can come at any moment.<\/p>\n https:\/\/github.com\/SevenW\/Lin-Transceiver-Library<\/a><\/p>\n