YMF795 Datasheet, PDF (4/45 Pages) YAMAHA CORPORATION – APL-2 Automobile sound Player-2

YMF795
■Block Description
1) Serial interface block
The block receives serial data and then identifies its Index data to send control data to each function block.
2) FIFO block
FIFO temporarily stores musical score data. Musical score data up to 32 can be stored. The musical score data are
processed in the sequencer when they are generated as sounds and those processed are deleted one after another.
When the amount of remaining data amount in FIFO reaches the value or less of register setting (IRQ point), it
outputs an interrupt signal to the outside to request the subsequent musical score data.
3) Sequencer block
When the sequencer receives the START command, it sequentially starts reading the musical score data which have
been stored in FIFO. The processed musical score data are deleted.
4) Timbre register block
The block stores timbre data in this register which can set up to 8 timbres. Settings of this register must be completed
before sound generation. The register is initialized by hardware reset; however, in the following operations, contents
of a register are not cleared, and the value written last is held.
• Software reset (CLR bit of Index32h)
• During power-down mode, and after its cancellation.
5) FM synthesizer block
The block synthesizes and generates timbres according to settings. Four sounds can be generated at the same time.
6) D/A, volume, and amplifier blocks
The output from the synthesizer is D/A-converted, and volume processing is performed. After that, the data is
output from the speaker or the earphone output pin.
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