A short introduction to the AWE hardware
Written by Mathias C. Hjelt
V2.0 - 18 Sep 95
Because the documentation and manuals that are bundled with the AWE don't
say very much about the actual structure of the hardware, and because there
has been quite a lot of misleading stuff floating around on the newsgroups,
I felt that there is a certain need for a page like this. Simply, it just
tries to explain the basic structure of the AWE and describe the various
parts and their tasks. There's also some stuff about the other AWE and SB
models.
The 32-series
Creative has got a whole family of 32-cards, and as usual, there's a lot of confusion regarding
the differences between all these models. Before you read all these pages you should know what's
what and why.
AWE32
AWE32 IDE
A new version of the AWE32 which has got an IDE CD-ROM interface and a new board layout. Everything
on my pages apply to this model too.
AWE32 VE (Value Edition)
Just a regular AWE without SIMM slots, Waveblaster connector and CSP chip (although there is a
socket for it so you can upgrade). A stripped-down card with a stripped-down price. Someone claimed
that the wave audio quality is lower than that of the real AWE. In any case, this model has obviously
been discontinued by now, and if you purchased one recently you can turn it in a get another card instead.
AWE32 VE IDE
An AWE32 VE + IDE CD-ROM interface, intended to replace the older version.
AWE32 PNP
A plug-and-play version of the AWE32.
Sound Blaster 32
Creative's new low-end card which is intended to replace the AWE32 VE models in the long run.
It's just like an AWE32 IDE, but has got no on-board RAM (but still have SIMM slots), and no
Waveblaster connector. The most important thing is that it uses the new Vibra chipset which
replaces the old SB16 chips used on the AWE, and as a result, it's got much cleaner sound
and costs less. Runs with AWE software although the mixer won't work right (the Vibra chip has
got no tone controls at all). Parts of these AWE texts apply to it.
Waveblaster II
Creative's own add-on synthesizer daughterboard, featuring an EMU8000. These pages are not about it,
but many things probably apply on it too.
From now on, these pages will use the names "AWE32" and "AWE", referring to the original AWE32
card with the old CD-ROM interfaces.
The basic structure of the AWE
Basically, but only theorethically, the AWE32 is like a SoundBlaster 16 MCD ASP plus the EMU subsystem.
This means that it has got all the regular SB16 functions (various CD-ROM interfaces, joystick/MIDI
interface, 16-bit 45kHz AD/DA conversion with real-time on-board compression / decompression, OPL3
FM synthesizer, WaveBlaster connector, etc) in addition to the new EMU-8000 Advanced WavEffects digital
sample playback synthesizer. The SB16-part is not, however, a 1:1 copy of the original card - the AWE
has got better wave audio playback and recording characteristics than the original SB16 cards.
Watching the newsgroups, I have noticed that many don't quite understand the difference between
the various parts of the AWE. There has for instance been confusion between the two signal processors
on the card, etc. To make sure everyone understands as much as possible of the basic structure of the AWE,
I've made a simplified functional block diagram of it. Note that this does not show how the
AWE is built up physically (ie how the chips are organized, how the functions are spread among the chips etc),
it just shows how the various instances and functions fit together and what their roles are. (Purists may
claim that this is not completely correct -- and I do of course have to agree, but that's not the point here.
The point is to make the whole thing as clear and comprehensible as possible. See below for further comments
on this.)
Here's a brief list of what the various instances are and do:
- Music synthesis stuff
- OPL3 - Yamaha's classic nauseating 4-op FM synthesizer
- EMU (AWE) 32/30-voice sample playback synth
- SIMM-slots + on-board 512k RAM + 1Mb ROM provides the EMU with sounds
- Effects Engine which generates effects like reverb & chorus or QSound for either the EMU or the OPL
- S/PDIF digital output, includes both synths + effects, makes it possible to use external pro DAC.
- DAC for converting both synths to analog
- Wave audio
- DAC for playback of stereo sound at 45kHz with a theorethical resolution of 16 bits. This is
where the sound effects usually come from in games etc. Software-synthesized music (like MODs) is also played
through this SB16-compatible channel, which some people insist on calling "digital channel".
- ADC for recording (digitizing) of stereo sound at 45kHz, again with a theorethical resolution of 16 bits.
- ASP / CSP, Creative's Advanced Signal Processor for:
- Real-time compression/decompression of sound during recording and playback
- Speech synthesis, for example using CL's TextAssist
- QSound on wave audio playback
- Other simple real-time processing of data flowing trough the wave audio channel
- Other logics
- MPU-401 and SB16-compatible MIDI interface for ordinary MIDI IN / OUT and optional Waveblaster-compatible
add-on synth
- Joystick interface
- CD-ROM interfaces for Sony's, Mitsumi's and Panasonic's / Creative's drives, alternatively an IDE & Panasonic
interface on AWE32 IDE cards
- The mixer
- Mixes and controls the volumes of:
- The synthesizers (EMU + OPL)
- The wave audio playback
- Line input
- Microphone input
- CD audio input (on-board connector)
- PC speaker input (on-board connector)
- Does AGC (automatic gain control) on the mic input
- Sends selected channels to the wave audio ADC for recording
- Controls volume, bass & treble of the stereo output signal, which finally is fed to the Line Out and
through a lousy amp to the Speaker Out connectors
What's wrong with that block diagram?
- The EMU synthesizer and the Effects Engine are not two separate devices, although they are separated
on the block diagram.
- The wave audio ADC and DAC reside in the same chip. This is the chip that usually (on other sound cards,
that is) is called CODEC, but CL seems to call it "DSP". It seems like it can do simple
ADPCM (Adaptive Differential Pulse Code Modulation) compression/decompression without any help from the actual
ASP / CSP.
- The stuff that handles the mixing, MIDI (MPU-401 & SB), joysticks and CD-ROMs is dealt with very briefly
on the block diagram. All these functions are actually spread among several chips and as a matter of fact not
very interesting.
For more and deeper information about all these things, see the page
called "AWE tech -
a look under the cover"