Yamaha YMF724F specifications B76 ..........SDMA Sound Blaster DMA-8 Channel Select

YMF724F

b[7:6] ..........SDMA: Sound Blaster DMA-8 Channel Select

These bits select the DMA channel for the Sound Blaster Pro block.

“0”:	DMA ch0
“1”:	DMA ch1	(default)
“2”:	reserved
“3”:	DMA ch3
b[10:8] ........SBIRQ: Sound Blaster IRQ Channel Select
These bits select the interrupt channel for the Sound Blaster Pro block.
“0”:	IRQ5	(default)
“1”:	IRQ7
“2”:	IRQ9
“3”:	IRQ10
“4”:	IRQ11
“5” - “7”:	reserved.
b[13:11] ......MPUIRQ: MPU401 IRQ Channel Select

When MIEN is set to “1”, these bits select the interrupt channel for the MPU401 block.

“0”:	IRQ5
“1”:	IRQ7
“2”:	IRQ9	(default)
“3”:	IRQ10
“4”:	IRQ11
“5” - “7”:	reserved

Same interrupt channels can be assigned to SBIRQ and MPUIRQ. b14..............SIEN: Serialized IRQ enable

DS-1 supports 3 types of interrupt protocols: PCI interrupt (INTA#), Legacy interrupt (IRQs) and Serialized IRQ. The interrupt protocol is selected with IMOD and SIEN as follows.

The interrupt channels for IRQs and Serialized IRQ are determined by SBIRQ and MPUIRQ,. Only one

protocol can be used at once.
SIEN	IMOD	Interrupt protocol
0	0	Legacy interrupt (IRQs)	(default)

01 PCI interrupt (INTA#)

1* Serialized IRQ

b15..............LAD: Legacy Audio Disable
This bit disables the Legacy Audio block.
“0”: Enables the Legacy Audio block
“1”: Disables the Legacy Audio block	(default)

When this bit is set to “1”, DS-1 does not respond to the I/O Target transaction for legacy I/O address on the PCI bus.

September 21, 1998

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