
KS0165
MULTIMEDIA AUDIO
10/
20
GENERAL DESCRIPTION
The
KS0165
is a highly integrated wavetable
synthesizer chip, designed to be part of high-
performance, low-cost multimedia audio systems.
The chip contains a complete 32-voice, 16-bit,
44.1kHz wavetable synthesizer with effect
processor, a high-performance 16-bit CPU,
compatibility with established standard audio
interfaces, and all necessary system glue logic.
With its on-chip CPU, an KS0165-based synthesizer
imposes absolutely minimal host CPU overhead.
Its hardware-based MPU-401 emulation completely
eliminates the memory overhead, software
compatibility, and stability problems of TSR-based
emulations. The following sections give a brief
description of the major functional blocks of the
KS0165.
H
OST
PC I
NTERFACE
All necessary ISA bus interface logic is completely
contained on-chip. This includes address decoding
for the MPU-401 emulation, control signal
interpretation, and optional data bus buffer control.
All PC interface control logic operates completely
asynchronously to the synthesizer/CPU logic.
Standard interfacing techniques are used to provide
a highly compatible and reliable interface.
The MPU-401 emulation can be decoded for any
one of four standard address ranges, as selected by
the BAS[1:0] pins. In addition, a serial MIDI interface
may be used, leaving the MPU-401 emulation
inactive. This mode is particularly useful for stand-
alone synthesizer modules and WaveBlaster-type
daughter board applications.
To better support non-PC-based applications,
including stand-alone applications where no host
CPU is available, the reset signal polarity is
programmable via the
HRSTPOL
pin, to
accommodate existing active high or active low
reset signals.
MPU-401 I
NTERFACE
The primary interface for communicating MIDI data
to/from the KS0165 is the on-chip MPU-401
emulation. This emulation provides the full hardware
functionality and partial software functionality of a
real MPU-401. MPU-401 UART mode is fully
supported, while a subset of the "intelligent" mode
commands are also supported. The intelligent mode
support currently provided is adequate to support
virtually all existing MPU-401 applications. All
hardware necessary to support full intelligent mode
is present, allowing more complete intelligent mode
software support to be added in the future if it
become necessary. The MPU-401 interface is used
for communicating MIDI and command data
between the PC and the on-board synthesizer, the
PC and external devices connected to the on-board
MIDI interface available through the joy stick
connector on the card bracket. Normally, the MIDI
UART under the control of the embedded CPU, so
that it can provide FIFO buffering of MIDI data.
However, the UART transmitter can also be directly
connected to the MPU-401 emulation. This allows
UART mode data transfers from the PC to external
MIDI devices to take place with no intervention on
the part of the CPU, although the CPU will still
intercept and process MPU-401 command data and
UART receive data. It is also possible for the on-
board synthesizer to directly process MIDI data from
external sources, if desired. Unlike a real MPU-401,
the emulation provides the optional capability of
generating transmit interrupts to the PC for
enhanced performance.
MIDI UART I
NTERFACE
The second of available interfaces for
communicating MIDI data to/from the KS0165 is the
on-chip of MIDI UART. This interface is always
active, and works independently from the MPU-401
emulation, allowing the KS0165 to easily be used in
stand-alone MIDI modules and WaveBlaster-type
daughter board applications.
E
MBEDDED
CPU
In sharp contrast to many other low-cost multimedia
audio solutions currently available, the KS0164 does
not rely on the host PC processor or a slow external
micro controller to drive the wavetable synthesizer.
Rather, the KS0164 contains a high-performance
custom-built 16-bit CPU incorporating such
advanced features as six different addressing
modes, a hardware multiplier, a barrel shifter, and a
peak execution rate of nearly 3 million instructions
per second. In addition to providing optimal
synthesizer audio quality, this reduces host PC CPU
overhead and the resulting degradation of
application/game performance. The considerable