Change operational mode of CAN transceiver
Transmitting this "wake signal" does not "wake" the transceiver.  What it's actually doing is the transceiver, when in "standby" mode, only allows through signals that have a dominant or recessive state that is longer than the filter time (5.5µs). Any transitions in the bus after a stable period of 5.5µs or more will get passed through.

The transceiver does not enter "normal" mode at that point. It is down to the CAN device to activate the transceiver through setting the STB pin LOW. 


  When pin RXD goes LOW to signal a wake-up request, a transition to Normal mode will not be triggered until STB is forced LOW.


Exactly what you send is of no consequence to the transceiver - only whether it has D and R states that are longer than 5.5µS.  It's up to the CAN device to interpret them and know if it should wake up the transceiver and place it in NORMAL mode.

And the MCP2515 also doesn't care what it receives.  When the WAKEIE bit is set it will cause the MCP2515 itself to wake from its sleep mode when anything is received - at which point it signals to the Arduino through its INT pin that it's woken up.

However your chosen library has no ability included in it to control the WAKEIE bit of MCP_CANINTF - only the TXxIF bits are supported.  So you will have to expand the library to provide that facility.

The general idea of operation is:


The transceiver lets through a "slow" signal (like transmitting 0b00110011)
The MCP2515 receives "something"
INT pin goes LOW and the Arduino reacts to it
The Arduino drives STB LOW and reception can proceed normally.


Note that it is the Arduino that will be controlling STB, not the MCP2515.