sak-xc164cm-8f40f-aa Infineon Technologies Corporation, sak-xc164cm-8f40f-aa Datasheet - Page 44

• Manufacturer Part Number: sak-xc164cm-8f40f-aa
• Description: Xc164cm - Automotive Controller With Can
• Manufacturer: Infineon Technologies Corporation

XC164CM
Derivatives
Functional Description
3.15
Clock Generation
The Clock Generation Unit uses a programmable on-chip PLL with multiple prescalers
f
to generate the clock signals for the XC164CM with high flexibility. The master clock
MC
is the reference clock signal, and is used for TwinCAN and is output to the external
f
f
system. The CPU clock
and the system clock
are derived from the master clock
CPU
SYS
f
f
f
either directly (1:1) or via a 2:1 prescaler (
=
=
/ 2). See also
Section
4.4.1.
SYS
CPU
MC
The on-chip oscillator can drive an external crystal or accepts an external clock signal.
The oscillator clock frequency can be multiplied by the on-chip PLL (by a programmable
factor) or can be divided by a programmable prescaler factor.
If the bypass mode is used (direct drive or prescaler) the PLL can deliver an independent
clock to monitor the clock signal generated by the on-chip oscillator. This PLL clock is
independent from the XTAL1 clock. When the expected oscillator clock transitions are
missing the Oscillator Watchdog (OWD) activates the PLL Unlock/OWD interrupt node
and supplies the CPU with an emergency clock, the PLL clock signal. Under these
circumstances the PLL will oscillate with its basic frequency.
The oscillator watchdog can be disabled by switching the PLL off. This reduces power
consumption, but also no interrupt request will be generated in case of a missing
oscillator clock.
Data Sheet
42
V1.4, 2007-03