Hardware Overview
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Different DSP versions are used on various versions of Sound Blaster family cards.
Over the years, the functionality of the DSP has been greatly enhanced. The later
versions of DSP are designed to be downward compatible with its earlier counterparts
with new features introduced. Generally, the DSP versions can be classified under
five majors categories: 1.xx , 2.00 , 2.01+ , 3.xx and 4.xx. In the chapter on
"Introduction to DSP Programming", the essential steps needed to program the DSP
are discussed. In the later chapter on "DSP Commands", various DSP commands are
discussed in details according to their function's category.
Mixer Chip
The main purpose of the mixer chip is to mix signals from different input sources and
to provide software volume control capabilities. All cards in the Sound Blaster
family, except SB2.0 and earlier version of Sound Blaster cards, has mixer chip.
Currently, there are three versions of mixer chip: CT1335 , CT1345 and CT1745.
Each version differs from the other by their ability to accept different number of
sources and to provide volume control resolution. CT1745, the latest version of
mixer chip, can provide a finer resolution of volume control. In the chapter on
"Mixer Chip Programming", each of these mixer chips as well as the included
register maps will be discussed in detail.
FM Synthesizer Chip
The FM synthesizer chip synthesizes the sounds of musical instruments. It tries to
approximate real instrument sounds by applying the Frequency Modulation (FM)
technique to sine waves.
There are two versions of FM synthesizer chips used on Sound Blaster cards;
YAMAHA OPL2 and YAMAHA OPL3. The OPL2 chip is used in earlier versions of
Sound Blaster Pro, SB2.0 and Sound Blaster. The later version of Sound Blaster Pro,
and Sound Blaster 16 use the YAMAHA OPL3 chip.
Please contact the respective vendor for detailed documentation on the FM
synthesizer chip if you are interested on the FM synthesizer chip programming.
