MC9S08GT16A Datasheet, PDF (13/300 Pages) Freescale Semiconductor, Inc – Microcontrollers

Section Number
Title
Page
Chapter 9
Internal Clock Generator (S08ICGV4)
9.1 Introduction ...................................................................................................................................125
9.1.1 Features ...........................................................................................................................127
9.1.2 Modes of Operation ........................................................................................................128
9.1.3 Block Diagram ................................................................................................................129
9.2 External Signal Description ..........................................................................................................129
9.2.1 EXTAL — External Reference Clock / Oscillator Input ................................................129
9.2.2 XTAL — Oscillator Output ............................................................................................129
9.2.3 External Clock Connections ...........................................................................................130
9.2.4 External Crystal/Resonator Connections ........................................................................130
9.3 Register Definition ........................................................................................................................131
9.3.1 ICG Control Register 1 (ICGC1) ....................................................................................131
9.3.2 ICG Control Register 2 (ICGC2) ....................................................................................133
9.3.3 ICG Status Register 1 (ICGS1) .......................................................................................134
9.3.4 ICG Status Register 2 (ICGS2) .......................................................................................135
9.3.5 ICG Filter Registers (ICGFLTU, ICGFLTL) ..................................................................135
9.3.6 ICG Trim Register (ICGTRM) .......................................................................................136
9.4 Functional Description ..................................................................................................................136
9.4.1 Off Mode (Off) ................................................................................................................137
9.4.1.1 BDM Active ..................................................................................................137
9.4.1.2 OSCSTEN Bit Set .........................................................................................137
9.4.1.3 Stop/Off Mode Recovery ..............................................................................137
9.4.2 Self-Clocked Mode (SCM) .............................................................................................137
9.4.3 FLL Engaged, Internal Clock (FEI) Mode .....................................................................138
9.4.4 FLL Engaged Internal Unlocked ....................................................................................139
9.4.5 FLL Engaged Internal Locked ........................................................................................139
9.4.6 FLL Bypassed, External Clock (FBE) Mode ..................................................................139
9.4.7 FLL Engaged, External Clock (FEE) Mode ...................................................................139
9.4.7.1 FLL Engaged External Unlocked .................................................................140
9.4.7.2 FLL Engaged External Locked .....................................................................140
9.4.8 FLL Lock and Loss-of-Lock Detection ..........................................................................140
9.4.9 FLL Loss-of-Clock Detection .........................................................................................141
9.4.10 Clock Mode Requirements .............................................................................................142
9.4.11 Fixed Frequency Clock ...................................................................................................143
9.4.12 High Gain Oscillator .......................................................................................................143
9.5 Initialization/Application Information ..........................................................................................143
9.5.1 Introduction .....................................................................................................................143
9.5.2 Example #1: External Crystal = 32 kHz, Bus Frequency = 4.19 MHz ...........................145
9.5.3 Example #2: External Crystal = 4 MHz, Bus Frequency = 20 MHz ..............................147
9.5.4 Example #3: No External Crystal Connection, 5.4 MHz Bus Frequency ......................149
9.5.5 Example #4: Internal Clock Generator Trim ..................................................................151
MC9S08GT16A/GT8A Data Sheet, Rev. 1
Freescale Semiconductor
13