Interrupt Routing - Yamaha LSI YMF744B Technical Manual

YMF744B

4. Interrupt Routing

DS-1S 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-1S are routed as shown below.
INTA#
IRQ5
IRQ7
IRQ9
IRQ10
IRQ11
SERIRQ#
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-1S 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.
INTA
ISA IRQ
SERIRQ
SIEN=0, IMOD=1
SIEN=0, IMOD=0
SIEN=1, IMOD=*
SIEN=0, IMOD=1
SIEN=0, IMOD=0
SIEN=1, IMOD=*
SIEN, IMOD
-46-
PCI Audio
IRQ
Sound Blaster Pro
Select Signal
SBIRQ[2:0]
IRQ
MPU401
Select Signal
MPUIRQ[2:0]
February 3, 1999