PI7C7300DNAE Pericom Semiconductor, PI7C7300DNAE Datasheet - Page 48

• Manufacturer Part Number: PI7C7300DNAE
• Description: IC PCI-PCI BRIDGE 3PORT 272-BGA
• Manufacturer: Pericom Semiconductor

Specifications of PI7C7300DNAE

• Applications: *
• Interface: *
• Voltage - Supply: *
• Package / Case: 272-PBGA
• Mounting Type: Surface Mount
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Operating Supply Voltage: 3 V to 3.6 V
• Supply Current (max): 660 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

5.4
5.4.1
5.4.2
Pericom Semiconductor
32 bits registers can both be set to the same value, while the lower base register is set
greater than the lower limit register. Otherwise, the upper 32-bit base must be greater
than the upper 32-bit limit.
VGA SUPPORT
PI7C7300D provides two modes for VGA support:
VGA MODE
When a VGA-compatible device exists downstream from PI7C7300D, set the VGA
mode bit in the bridge control register in configuration space to enable VGA mode.
When PI7C7300D is operating in VGA mode, it forwards downstream those transactions
addressing the VGA frame buffer memory and VGA I/O registers, regardless of the
values of the base and limit address registers. PI7C7300D ignores transactions initiated
on the secondary interface addressing these locations.
The VGA frame buffer consists of the following memory address range:
Read transactions to frame buffer memory are treated as non-prefetchable. PI7C7300D
requests only a single data transfer from the target, and read byte enable bits are
forwarded to the target bus.
The VGA I/O addresses are in the range of 3B0h–3BBh and 3C0h–3DFh I/O. These I/O
addresses are aliases every 1KB throughout the first 64KB of I/O space. This means that
address bits <15:10> are not decoded and can be any value, while address bits [31:16]
must be all 0s. VGA BIOS addresses starting at C0000h are not decoded in VGA mode.
VGA SNOOP MODE
PI7C7300D provides VGA snoop mode, allowing for VGA palette write transactions to
be forwarded downstream. This mode is used when a graphics device downstream from
PI7C7300D needs to snoop or respond to VGA palette write transactions. To enable the
mode, set the VGA snoop bit in the command register in configuration space. Note that
PI7C7300D claims VGA palette write transactions by asserting DEVSEL# in VGA
snoop mode.
When VGA snoop bit is set, PI7C7300D forwards downstream transactions within the
3C6h, 3C8h and 3C9h I/O addresses space. Note that these addresses are also forwarded
as part of the VGA compatibility mode previously described. Again, address bits
<15:10> are not decoded, while address bits <31:16> must be equal to 0, which means
that these addresses are aliases every 1KB throughout the first 64KB of I/O space.
VGA mode, supporting VGA-compatible addressing
VGA snoop mode, supporting VGA palette forwarding
000A 0000h–000B FFFFh
Page 48 of 107
3-PORT PCI-TO-PCI BRIDGE
November 2005 - Revision 1.01
PI7C7300D