Motorola MC68VZ328 - Manual (Page 41)

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) conversion. Using these three 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 provides higher resolution for better sound
quality. Users can enable both PWMs at the same time to generate a mixed PWMO signal. See Chapter 15,
“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 memory
space, which is 0xFFFC0000 to 0xFFFCFFFF, is covered by the EMUCS signal and primarily dedicated 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 Chapter 16, “In-Circuit Emulation,” for more details.
1.3.15 Bootstrap Mode
The bootstrap mode is designed to allow the initialization of a target system and the ability to download
programs or data to the target system RAM using either the UART 1 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 programs
stored in flash memory. Simple hardware debug functions may be performed on the target system using the
bootstrap utility program BBUGV.EXE, which is available on the following World Wide Web site:
http://www.Motorola.com/DragonBall. See Chapter 17, “Bootstrap Mode,” for more information about
this mode.