MC68HC908LD64 Datasheet, PDF (95/362 Pages) Freescale Semiconductor, Inc – Microcontrollers

Data Sheet — MC68HC908LD64
Section 7. Oscillator (OSC)
7.1 Contents
7.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
7.3 Oscillator External Connections . . . . . . . . . . . . . . . . . . . . . . . .96
7.4 I/O Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
7.4.1 Crystal Amplifier Input Pin (OSC1). . . . . . . . . . . . . . . . . . . . 97
7.4.2 Crystal Amplifier Output Pin (OSC2) . . . . . . . . . . . . . . . . . . 97
7.4.3 Oscillator Enable Signal (SIMOSCEN). . . . . . . . . . . . . . . . . 97
7.4.4 External Clock Source (OSCXCLK) . . . . . . . . . . . . . . . . . . . 97
7.4.5 Oscillator Out (OSCOUT). . . . . . . . . . . . . . . . . . . . . . . . . . . 97
7.5 Low Power Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
7.5.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98
7.5.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98
7.6 Oscillator During Break Mode. . . . . . . . . . . . . . . . . . . . . . . . . . 98
7.2 Introduction
The oscillator circuit is designed for use with crystals or ceramic
resonators. The oscillator circuit generates the crystal clock signal,
OSCXCLK, at the frequency of the crystal. This signal is divided by two
before being passed on to the SIM for bus clock generation. Figure 7-1
shows the structure of the oscillator. The oscillator requires various
external components.
The MC68HC908LD64 operates from a nominal 24MHz crystal or
external clock, providing an 8MHz internal bus clock. The 24MHz clock
is required for various modules, such as the CGM and USB.
MC68HC908LD64 — Rev. 3.0
Freescale Semiconductor
Oscillator (OSC)
Data Sheet
95