kiki@uhunix1.uhcc.Hawaii.Edu (J. W. Wine) (05/20/91)
[usurped from Yamaha manual #LSI 222030]
To digitally produce the sounds created by a piano, violin, or flute, the
number of operations which must be performed requires uninterrupted micro-
processor operation. However, using the OPN FM system, it is possible to
create rich musical sounds.
The FM system can also be used as a synthesizer to produce a wide range of
sounds. OPN functions are compatible with the YM2149 (SSG) and AY3-8910.
Although these devices can only generate square waves, they are in widespread
use due to simplicity of control; systems which use them can be enhanced by
replacing them with the OPN chips.
The OPN LSI is manufactured using Yamaha's Si-gate NMOS process, It includes
two sound sources: the FM system and the SSG sound sources. Since these sound
sources can each produce three musical sounds, a wide variety of synthesized
tones can be produced.
Features
--------
* FM system produces up to three different sounds at same time
* Each of the above three sounds allows sound effects and composite sine waves
(CSM) to be created.
* Three square wave sounds and white noise for compatibility with SSG
* Two 8-bit general purpose I/O ports
* Wide range of operating frequencies available with internal clock divider
[ Adds 108 additional control registers to the Yamaha YM2149 core. The reg-
isters control 2 timers, ADSR envelope w/ 96 dB range, dividers, feedback,
etc. Output of OPN is sent serially to a 16-bit D/A converter, YM3014 ]
Principal Functions
-------------------
a) FM sound generator w/ three modes:
I) Music - four operator cells allow FM sound source to produce
three sounds simultaneously. Eight operator cells
combinations are possible.
II) Effects - frequency parameters of four operator cells can be changed
so that one of three sounds produce a sound effect while
the other two are use as in the music mode.
III) Voice - one of the three sounds used in the composite sine wave
mode. Can be used simultaneously with two other sounds
in music mode.
[Configuration tables are given for brass, string, piano, flute, oboe, etc.
Production of chorus and tremolo effects also possible.]
b) SSG - Apart from FM generator, this section functions as YM2149 chip, so
a total of six sounds can be produced
c) Two timers are provided and can be used as reference signals for key switch
scanning and tempo clocking.
Pin configuration
-------------
Vss | 1 40| d0
d1 | 2 39| s clock
. | 3 38| m clock
. | 4 37| a0
. | 5 36| /RD
. | 6 35| /WR
. | 7 34| /CS
d7 | 8 33| IOb7
IOa7 | 9 32| .
. |10 31| .
. |11 30| .
. |12 29| .
. |13 28| .
. |14 27| .
. |15 26| IOb0
IOa0 |16 25| /IRQ
agnd |17 24| /IC
analog c |18 23| op [serial out to D/A]
" b |19 22| sh [D/A sync signal]
" a |20 21| Vcc
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