Motorola MC68VZ328 4.1 Introduction to the Clock Generation Module

4-2 MC68VZ328 User’s Manual 
Introduction to the Clock Generation Module
4.1 Introduction to the Clock Generation Module
The CGM produces four clock signals:
• CLK32—A low-frequency reference clock used by almost every module
• DMACLK—Used to create the remaining two clocks, and serves as DMA clock for the LCD
controller
• SYSCLK—Used by most modules, including the CPU
• LCDCLK—Used as reference by the LCD
The distribution of the clock signals generated by the CGM is shown in Table4-1. With the exception of
the CLK32 signal, the frequency of the clock signals can be individually programmed.
Table 4-1. CGM Clock Signal Distribution
Used by or Available To CLK32 SYSCLK DMACLK LCDCLK
CLKO/PF2 pin X
DRAM controller X X X
LCD controller X X
PCM X
PWM X X
RTC X
SPIs X
Timers X X
UARTs X