Modules of the MC68VZ328
Introduction 1-11
1.3.13 Pulse-Width Modulators (PWM)
The MC68VZ328 has two pulse-width modulators (PWMs). Each of the pulse-width modulators has three
modes of operation—playback, tone, and digital-to-analog (D/A) c onvers ion. Us ing thes e th ree modes, the
PWM can be used to play back high-quality digital sounds, produce simple tones, or convert digital data
into analog waveforms. The 8-bit PWM contains a 5-byte FIFO that enhances the system performance by
reducing the number of interrupts to the CPU. The 16-bit PWM provide s high er r esolut ion f or be tter s ound
quality. Users can enable both PWMs at the same time to generate a mixed PWMO signal. See Chapter15,
“Pulse-Width Modulator 1 and 2,” for more detailed information about the configuration and operation of
these devices.
1.3.14 In-Circuit Emulation Module
The in-circuit emulation module is designed for low-cost emulator development purposes. System memo ry
space, which is 0xFFFC0000 to 0xFFFCFFFF, is covered by the EMUCS signa l and pr imarily d edicated to
the emulator debug monitor. However, the EMUCS signal can be used to select the monitor ROM or
system I/O port. Keep in mind that if the monitor ROM is selected, the system must boot up in emulator
mode. Refer to Chapter16, “In-Circuit Emulation,” for more details.
1.3.15 Bootstrap Mode
The bootstrap mode is designed to allow the init ia lization of a target system and the ability to download
programs or data to the target system RAM using either the UART1 or UART 2 controller. See
Chapter 14, “Universal Asynchronous Receiver/Transmitter 1 and 2,” for information on operating and
programming the UART controllers. Once a program is downloaded to the MC68VZ328, it can be
executed, providing a simple debugging environment for failure analysis and a channel to update pr ograms
stored in flash memory. Simple hardware debug functions may be performed on the tar get system u sing the
bootstrap utility program BBUGV.EXE, which is available on the following World Wide Web site:
http://www.Motorola.com/DragonBall. See Chapter17, “Bootstrap Mode,” for more information about
this mode.