More development - checkin

README.md

@@ -1,17 +1,19 @@
 # MD_YM2413
 
-The SN76489 Digital Complex Sound Generator (DCSG) is a TTL-compatible programmable
-sound generator chip from Texas Instruments. It provides:
-- 3 programmable square wave tone generators (122Hz to 125kHz)
-- 1 noise generator (white noise and periodic noise at 3 different frequencies)
-- 16 different volume levels
-- Simultaneous sounds
+The YM2413, OPLL, is a cost-reduced FM synthesis sound chip manufactured 
+by Yamaha Corporation and based on their YM3812 (OPL2).
+
+The simplifications mean that the YM2413 can only play one user-defined 
+instrument at a time, with an additional 15 read-only hard-coded instrument
+profiles available. The IC can operate as 9 channels of instruments or 6 
+channels with melodic instruments and 5 with percussion instruments.
+
+Its main historical application was the generation of music and sound effects in 
+microprocessor systems. It was extensively used in early game consoles, arcade games, 
+home computers and low-cost synthesizer keyboards.
 
 This library implements functions that manage the sound and noise generation interface
-to the SN76489 IC through a clean API encapsulating the basic functionality provided
+to the YM2413 IC through a clean API encapsulating the basic functionality provided
 by the hardware.
 
-Additionally, the library provides programmable ADSR envelope management of the sounds
-produced, allowing a more versatile sound output with minimal programming effort.
-
 [Library Documentation](https://majicdesigns.github.io/MD_YM2413/)