MC68HC908KX8 Datasheet, PDF (109/310 Pages) Motorola, Inc – Microcontrollers

Internal Clock Generator Module (ICG)
Functional Description
7.4.4 Clock Monitor Circuit
The ICG contains a clock monitor circuit which, when enabled, will
continuously monitor both the external clock (ECLK) and the internal
clock (ICLK) to determine if either clock source has been corrupted. The
clock monitor circuit, shown in Figure 7-4, contains these blocks:
• Clock monitor reference generator
• Internal clock activity detector
• External clock activity detector
CMON
FICGS
IBASE
ICGEN
EXTXTALEN
EXTSLOW
CMON
FICGS
IBASE
ICGEN
ICLK
ACTIVITY
DETECTOR
EREF
IOFF
ICGS
IBASE
ICGON
EREF
EXTXTALEN
EXTSLOW
ECGS
REFERENCE
GENERATOR
ECLK
ECGEN
ESTBCLK
IREF
IOFF
ICGS
ECGEN
ECLK
ESTBCLK
IREF
ECGEN
ECLK
ECLK
ACTIVITY
DETECTOR
ECGS
CMON
EOFF
ECGS
EOFF
NAME
NAME
CONFIGURATION (OR MOR) REGISTER BIT
TOP LEVEL SIGNAL
NAME
NAME
REGISTER BIT
MODULE SIGNAL
Figure 7-4. Clock Monitor Block Diagram
MC68HC908KX8 • MC68HC908KX2 • MC68HC08KX8 — Rev. 1.0
MOTOROLA
Internal Clock Generator Module (ICG)
Technical Data
109