Recommend single-node operation #158
Description
We should add a section to the CAN Frame Transport TN that discusses operation of a single CAN node. Something like:
CAN transport requires that every transmitted frame be acknowledged by at least one other node. If a CAN node is not connected to any other nodes, its first frame transmission will fail, be retransmitted several times, then the node's CAN adapter will go to an error state.
It's useful for OpenLCB CAN nodes to be able to operate by themselves. The user might want to take some inputs to the node and drive outputs from that same node, without any other hardware being attached.
Node implementers should, but do not have to, handle their CAN errors such that their node can operate independently. It's helpful if that independent operation mode is shown on the board's LEDs for help in debugging the CAN network connections.