Re: CAN as UART?
The CAN-bus works with differential signals, so it will not work the way you want it.
The question is, if you would like to use the same pin of the uC or use the same wires outside...
If you just want the same pins, you could put latches between the uart-controller and the can-controller, as both get standard logic signals.
But if you have a hardware uart and a hardware can then they will probably be on different io-pins and you can't reconfigure that.
If you want to use the same wire, you should probably take analog switches, so you can choose the active signal on the wire.
But both options will cost extra pins of the uC, no way out.
Just hooking up the signals will result in undefined reactions of the uart and the can-controller. Second you need to terminate your can-wires whereas your uart may not be terminated.
Hope I could help you.