saf-xc878m-16ffi5v Infineon Technologies Corporation, saf-xc878m-16ffi5v Datasheet - Page 82

• Manufacturer Part Number: saf-xc878m-16ffi5v
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Infineon Technologies Corporation

3.8
The Clock Generation Unit (CGU) allows great flexibility in the clock generation for the
XC87x. The power consumption is indirectly proportional to the frequency, whereas the
performance of the microcontroller is directly proportional to the frequency. During user
program execution, the frequency can be programmed for an optimal ratio between
performance and power consumption. Therefore the power consumption can be
adapted to the actual application state.
Features
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The CGU consists of an oscillator circuit and a PLL. In the XC87x, the oscillator can be
from either of these two sources: the on-chip oscillator (4 MHz) or the external oscillator
(2 MHz to 20 MHz). The term “oscillator” is used to refer to both on-chip oscillator and
external oscillator, unless otherwise stated. After the reset, the on-chip oscillator will be
used by default.The external oscillator can be selected via software. In addition, the PLL
provides a fail-safe logic to perform oscillator run and loss-of-lock detection. This allows
emergency routines to be executed for system recovery or to perform system shut down.
1) SAK product variant does not support power-down mode.
Data Sheet
Phase-Locked Loop (PLL) for multiplying clock source by different factors
PLL Base Mode
Prescaler Mode
PLL Mode
Power-down mode support
Clock Generation Unit
1)
75
Functional Description
XC87xCLM
V1.5, 2011-03