-CPI Clock- Can Protocol Interface Clock
- This CLK_SRC bit of CTRL(control register) selects the clock source to
- the CAN Protocol Interface(CPI) to be either the peripheral clock
- (driven by the PLL) or the crystal oscillator clock. The selected clock
- is the one fed to the prescaler to generate the Serial Clock (Sclock).
- The PRESDIV field of CTRL(control register) controls a prescaler that
- generates the Serial Clock (Sclock), whose period defines the
- time quantum used to compose the CAN waveform.