From: kiki@uhunix1.uhcc.Hawaii.Edu (J. W. Wine) Subject: Yamaha FM-SSG music chip Date: 20 May 91 10:09:37 GMT [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 -------------