Fusion 878A
6.0 Control Register Definitions–Function 1
PCI Video Decoder
6.2 PCI Configuration Registers (Header)
100600B
Conexant
6-5
0x2C—Subsystem ID and Subsystem Vendor ID Register
0x34—Capabilities Pointer Register
0x3C—Interrupt Line, Interrupt Pin, Min_Gnt, Max_Lat Register
Bits
Type
Default
Name
Description
[31:16]
RW
0x0000
Subsystem ID
Vendor specific.
[15:0]
RW
0x0000
Subsystem
Vendor ID
Identifies the vendor of the add-on board or subsystem assigned by PCI
SIG.
Bits
Type
Default
Name
Description
[7:0]
RO
0x44
Cap_Ptr
DWORD-aligned byte address offset in configuration space to the first item
in the list of capabilities.
Bits
Type
Default
Name
Description
[31:24]
RO
0xFF
Max_Lat
Requires bus access every 64 µs, at a minimum, in units of 250 ns. Affects
the desired settings for the latency timer value. This register is set to the
max value even though the audio can tolerate up to 287 µs bus access
latency (a 0 setting would indicate no latency requirements).
[23:16]
RO
0x04
Min_Gnt
Requires a minimum grant burst period of 1 µs to empty data FIFO, in units
of 250 ns. Affects the desired settings for the latency timer value. Set for 32
DWORDs, 33 MHz, with 0 wait states.
[15:8]
RO
0x01
Interrupt Pin
Fusion 878A interrupt pin is connected to INTA, the only one usable by a
single function device.
[7:0]
RW
Interrupt Line
The Interrupt Line register communicates interrupt line routing information
between the POST code and the device driver. The POST code initializes
this register with a value specifying to which input (IRQ) of the system
interrupt controller the Fusion 878A interrupt pin is connected. Device
drivers can use this value to determine interrupt priority and vector
information.