Yamaha YMF724F specifications Interrupt Routing, Digital Audio Interface, Serialized IRQ

YMF724F

4. Interrupt Routing

DS-1 supports three types of interrupts, interrupt signal on the PCI bus (INTA#), interrupt signal on the ISA bus (IRQ[5,7,9,10,11]), and Serialized IRQ.

The IRQs on DS-1 are routed as shown below.

INTA#	INTA			PCI Audio
IRQ5	SIEN=0, IMOD=1	Selector
	SIEN=1, IMOD=*		IRQ
	SIEN=0, IMOD=0			Sound Blaster Pro
IRQ7			Select Signal
IRQ9	ISA IRQ
				SBIRQ[2:0]
IRQ10
IRQ11	SIEN=0, IMOD=1	Selector
	SIEN=0, IMOD=0		IRQ	MPU401
	SIEN=1, IMOD=*
SERIRQ#	SERIRQ		SIEN, IMOD
			Select Signal
				MPUIRQ[2:0]

PCI Audio can only use INTA#, but the Sound Blaster Pro and MPU401 blocks of the Legacy Audio Block can use any of the three protocols.

The protocol can be switched using 40-43h (Legacy Audio Control Register) of the PCI Configuration Register.

4-1. Serialized IRQ

Serialized IRQ is a method to encode IRQs of 15 channels into one signal.

DS-1 provides the SERIRQ# pin to support Serialized IRQ.

Only one channel out of the 5 channels, IRQ5, IRQ7, IRQ9, IRQ10, and IRQ11, can be encoded into the IRQ/Data frame of Serialized IRQ.

The IRQ channel is selected using 40h-43h (Legacy Audio Control Register) of the PCI Configuration Register.

5. Digital Audio Interface

DS-1 only supports SPDIF output conforming to IEC958. The only supported Fs is 48 kHz. It can be

selectable from the Dolby Digital (AC-3) encoded data or the result of Digital Mixing.

September 21, 1998

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