I have a college assignment where I need to get serial output, the Ethernet shield and SPI communication with other boards to work. We are not allowed to use any existing libraries, though we can use them as strong inspiration, as long as we are able to explain every line we have in our final code.
Since there appears to be a lack of C resource I spent lots of time trying to reverse engineer the CPP libraries but I am hopelessly overwhelmed by anything beyond getting a pure C blinky to run.
Do you have any idea how I should approach this? Are there C resources about the Ethernet shield and Arduino SPI?