YMF715E Datasheet, PDF (34/54 Pages) YAMAHA CORPORATION – OPL3 Single-chip Audio System 3

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Interrupt Channel configuration (R/W):
Index
D7
D6
D5
D4
D3
D2
D1
D0
OPL3
IRQ-B
MPU
SB
WSS
OPL3
IRQ-A
MPU
SB
WSS
There are four devices (WSS (Windows Sound System CODEC), SB (Sound Blaster
compatible portion), OPL3, MPU (MPU401)) that can be an interrupt source. This
register specifies what interrupt source is routed to two physical interrupt (IRQA and
IRQB) of OPL3-SA3. The device written to ”1” is assigned to the corresponding interrupt.
And by writing all “1” to upper or lower half byte, it is possible to share all interrupt
sources to a single physical interrupt line.
default : 69h
IRQ-A: WSS + OPL3
IRQ-B: SB + MPU401
Notice)
Do not assign a device to both IRQA and IRQB.
Interrupt (IRQ-A) status (RO):
Index
D7
D6
D5
D4
D3
D2
D1
D0
04h
-
MV
OPL3 MPU
SB
TI
CI
PI
This register is the status register that indicates which is the interrupt source of IRQA.
When an interrupt occurs, the corresponding bit becomes “1” and its flag (except MV bit)
is cleared when the interrupt routine is completed. This register is not cleared by writing
to this register.
MV...
Hardware Volume Interrupt Flag : If configured VEN=1(index 0Ah, D7
bit), the interrupt occurs when either /VOLUP or /VOLDW is low level or
when both are low level to request mute. The interrupt will be posted in
the IRQ-A channel, if IRQ-A MV=1 (index 17h, D4 bit).
Note that when the muting is in effect, the subsequent mute requests which
does not change any register contents will generate interrrupts. The
ignored UP/DOWN requests (UP requests with 0dB Volume attn.,
DOWN requests with -30dB) will not generate interrupts.
This bit is cleared upon host's reading the Master Volume Lch register at
OPL3...
index 07h.
Internal FM-synthesizer Timer Flag : Note that this flag will become
undefined for the configurations (SEL=3,4,7) using external synthesizer
MPU...
SB...
(i.e. OPL4-ML/ML2).
MPU401 Interrupt Flag
Sound Blaster compatible Playback Interrupt Flag
TI...
Timer Flag of CODEC
CI...
Recording Flag of CODEC
PI...
Playback Flag of CODEC
May 21, 1997
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