YMF721 Datasheet, PDF (12/41 Pages) LSI Computer Systems – FM + Wavetable Synthesizer LSI

YMF721
<Power Down in>
Command write “FDh”
Synthesizer clock disable
~30msec
Status read GBUSY=0
~3msec
<Power Down out>
Control write PDY=1, PDX=0
(wait time ~100 msec)
Control write PDY=0, PDX=0
Synthesizer clock enable
all clock (X’tal)disable
Normal Operation
Power down sequence when connected with ISA bus
5-1-2. No ISA BUS Connect System
When YMF721 (OPL4-ML2) is not connected with ISA bus, power down operation can be controlled
by sending Yamaha's original System Exclusive Message as the MIDI data. The System Exclusive
Message includes the following three byte ID.
43h, 79h, 04h : Yamaha YMF721(OPL4-ML2) ID
The System Exclusive Message is as follows.
F0h, <Yamaha YMF721(OPL4-ML2) ID>, <Command>, <Data>, F7h
YMF721 (OPL4-ML2) supports the following commands and data.
Command
0Eh
0Fh
Data
6Dh
6Bh
Function
Power Down Command
Internal Micro-processor Reset Command
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July 10, 1997