YMF721 Datasheet, PDF (8/41 Pages) LSI Computer Systems – FM + Wavetable Synthesizer LSI

YMF721
1-2. System without MPU401 UART
This section describes an example of a system that does not have MPU401 UART in it.
In this example, MPU401 UART of YMF721 (OPL4-ML2) is used.
FM synthesizer of this LSI is compatible with applications that support AdLib/Sound Blaster, and Wavetable
synthesizer is compatible with applications that support MPU401.
SA15-0
AEN
Lch out
Lch
Rch out
Rch
/OPLCS
/MPUCS
FSP
RXD
/PDIN
MCLK ^/PDOUT
BCLK ^CLKO
LRCK ^BCO
SDATA ^LRO
DO2
ARDY
RESET
A2-0
/IOW
/IOR
ADB7-0
ABDIR
IOCHRDY
RESETDRV
SA2-0
/IOW
/IOR
SD7-0
Note :
For the above case, MPU401 port of YMF721 (OPL4-ML2) must be made active because the system does not
have MPU401 UART in it. Addresses of standard ports through which reading or writing of registers of
YMF721 (OPL4-ML2) is made are as follows.
1) /OPLCS
: 388 - 38Fh (8byte)
2) /MPUCS
: 330 - 331h (2byte)
As a source of master clock for YMF721 (OPL4-ML2), use a crystal oscillator by connecting it to XI and
XO pins, or use the clock of 33.8688 MHz from the system. Connect BCO, LRO, DO2, /PDOUT and
CLKO directly to YAC516 (DAC16-L) as shown to convert serial data output to analog signal. Then, it is
recommended to amplify the volume of source of YMF721 through the suitable gain as shown for the
purpose of equalizing the volumes of multiple sources.
-8-
July 10, 1997