MC68HC08AZ60ACFU MOTOROLA [Motorola, Inc], MC68HC08AZ60ACFU Datasheet - Page 365

• Manufacturer Part Number: MC68HC08AZ60ACFU
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

MC68HC08AZ60A — Rev 0.0
MOTOROLA
CGM
MSCAN08
NOTE:
OSC
The clock source bit (CLKSRC) in the MSCAN08 module control register
(CMCR1) (see
defines whether the MSCAN08 is connected to the output of the crystal
oscillator or to the PLL output.
The clock source has to be chosen such that the tight oscillator tolerance
requirements (up to 0.4%) of the CAN protocol are met.
If the system clock is generated from a PLL, it is recommended to select
the crystal clock source rather than the system clock source due to jitter
considerations, especially at faster CAN bus rates.
A programmable prescaler is used to generate out of the MSCAN08
clock the time quanta (Tq) clock. A time quantum is the atomic unit of
time handled by the MSCAN08.
2
Figure 21-7. Clocking Scheme
CGMXCLK
MSCAN08 Controller (MSCAN08)
PLL
CLKSRC
MSCAN08 Module Control Register 0
2
2
PRESCALER
(1 .. 64)
MSCAN08 Controller (MSCAN08)
BCS
(2 * BUS FREQ.)
Advance Information
on page 377)
MSCANCLK
CGMOUT
(TO SIM)
Clock System
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