Fusion 878A
5.0 Control Register Definitions-Function 0
PCI Video Decoder
5.2 PCI Configuration Registers (Header)
100600B
Conexant
5-5
0x3C
—
Interrupt Line, Interrupt Pin, Min_Gnt, Max_Lat Register
Min_Gnt and Max_Lat values are dependent on target performance (TRDY) and video mode (scale factors and
color format). These values were chosen for best case target (0 wait state) and worst-case video delivery
(full-resolution 32-bit RGB).
0x34
—
Capabilities Pointer Register
0x40
—
Device Control Register
Bits
Type
Default
Name
Description
[31:25]
RO
0x28
Max_Lat
Requires bus access every 10 µs, at a minimum, in units of 250 ns. Affects
the desired settings for the latency timer value.
[24:16]
RO
0x10
Min_Gnt
Requires a minimum grant burst period of 4 µs to empty data FIFO, in units of
250 ns. Affects the desired settings for the latency timer value. Set for 128
DWORDs, 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
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.
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
[7:3]
RO
00000
Reserved
[2]
RW
0
EN_VSFX
Enables VIA/SIS PCI controller compatibility mode for both Functions 0 and 1.
0 = Disable
1 = Enable
[1]
RW
0
EN_TBFX
Enables 430FX PCI controller compatibility mode for both Functions 0 and 1.
0 = Disable
1 = Enable
[0]
RW
0
SVIDS_EN
Enables writes to the Subsystem Vendor ID register for both Functions 0 and 1.
0 = Disable
1 = Enable
NOTE(S):
These control bits affect both Function 0 and Function 1.