I'm thinking about this part of this board :
As you can see, there is a resistor in the red rectangle (R26). my question is what is the usage of this resistor?
Well being a resistor for D14(CANRX) is acceptable (because the supply of the MCP2551 is +5V but the STM32F103RBT6 is 3.3V (logic level)) but for D24(CANTX) it doesn't make sense to me.
Note that I have used this circuit for my CAN bus without R26 and R27 resistors and it works very fine.