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YMF744B
February 3, 1999
-20-
b14..............SIEN: Serialized IRQ enable
DS-1S 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)
0
1
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-1S does not respond to the I/O Target transaction for legacy I/O address on
the PCI bus.
42-43h: Extended Legacy Audio Control
Read / Write
Default: 0000h
Access Bus Width: 8, 16, 32-bit
b15
b14
b13
b12
b11
b10
b9
b8
b7
b6
b5
b4
b3
b2
b1
b0
IMOD
SBVER
SMOD
-
-
MAIM
-
-
-
-
-
-
-
-
b8................MAIM: MPU401 Acknowledge Interrupt Mask
This bit determine whether interrupt is asserted when the acknowledge, which is occurred by changing
MPU401 mode form default to UART, is returned.
“0”: Interrupt is asserted when the acknowledge is returned.
(default)
“1”: Interrupt is masked when the acknowledge is returned.
b[12:11] ......SMOD: SB DMA mode
These bits determine the protocol to achieve the DMAC(8237) function on the PCI bus.
“0”:
PC/PCI
(default)
“1”:
reserved
“2”:
Distributed DMA
“3”
reserved