This example assigns MIO pin 45 to the clock input reference for the CAN controller. Configure MIO pin 45 for the external CAN reference clock. These steps refer to the IOU_SLCR register set.
1.Route the reference clock. Write 32h'0000_1200 to the MIO_PIN_45 register.
2.Disable the output driver. Write a 1 to the MIO_MST_TRI1 [PIN_45_TRI] bit.
3.Select CMOS input (not Schmitt). Write 0 to BANK1_CTRL3  bit.
4.Select the internal pull-up resister. Write 1 to BANK1_CTRL4  bit.
5.Enable the internal pull-up resister. Write 1 to BANK1_CTRL5  bit.
The output controls, [drive0], [drive1], and [slow_fast_slew_n] do not need programming, but it is recommended to select minimum drive and slow slew rate. The voltage applied to PSIO bank 1 can be read using the BANK1_STATUS  bit.
Configure the reference clock at the controller. These steps refer to the IOU_SLCR.CAN_MIO_CTRL register.
6.Select the clock path to use MIO pin 45. Write 1 to the [CAN_REF_SEL] bit.
7.Select MIO Pin 45. Write 2Dh (45d) to the [CAN_MUX] bit.
8.Choose an active reference clock edge for RX using the [CAN_RXIN_REG] bit.