38.5.2 Clocks

An AHB clock CLK_CANx_AHB (where x =0,1,2,3,4,5) is required to clock the CAN. The CAN AHB BUS interface clocks are enabled by default on reset. This clock can be configured in the Main Clock peripheral (MCLK) before using the CAN, and the default state of CLK_CANx_AHB can be found in the AHBMASK register of the MCLK (Main Clock Controller) module.

A generic clock GCLK_CANx (where x =0,1,2,3,4,5) is required to clock the CAN. This clock must be configured and enabled in the generic clock controller before using the CAN.

This generic clock is asynchronous to the bus clock (CLK_CANx_AHB). Due to this asynchronicity, writes to certain registers will require synchronization between the clock domains.

References:

Peripheral Clock Masking - MCLK

Generic Clock Controller - GCLK