Intel® 82870P2 PCI/PCI-X 64-bit Hub 2 (P64H2) Datasheet
The Intel® 82870P2 PCI/PCI-X 64 Hub 2 (P64H2) is a peripheral chip that performs PCI bridging functions between hub interface and the PCI Bus. On the primary bus, the P64H2 utilizes a 16-bit data bus to interface with the hub interface, and on the secondary bus the P64H2 supports two 64-bit PCI bus interfaces. Either one of the secondary PCI bus interfaces can be configured to operate in PCI or PCI-X mode. Each PCI interface contains an I/O APIC with 24 interrupts and a hot plug controller supporting each PCI bus segment.
Primary Bus (the Hub Interface)
The Primary bus is the hub interface between the MCH and P64H2. This 16-bit data interface provides support for 32-bit and 64-bit addressing. The base clock is 66 MHz.
Secondary Bus (2 PCI Bus Interfaces)
The P64H2 has two PCI Bus interfaces (PCI Bus A and PCI Bus B). In this document these buses are referred to as the secondary buses. These interfaces can be independently configured as either a PCI Bus or PCI-X Bus. PCI Bus extensions are also provided. There is 64-bit addressing outbound, with the capability to assert DAC. full 64 bit addressing inbound is supported. The inbound packet size is based on the cache line size of the platform.
I/O space can be programmed to 1 KB granularity. If inbound reads are retried, they will be moved to the side so that posted writes and completion packets can pass. I/O reads and writes on PCI will no longer be forwarded to the hub interface, nor will they be forwarded to the other PCI interface.
The PCI Bus interface is compliant with the PCI Local Bus Specification, Revision 2.2. The PCI-X interface is compliant with the PCI-X Addendum to the PCI Local Bus Specification, Revision 1.0. PCI-X provides enhancements over PCI that enable faster and more efficient data transfers. For PCI Mode, the P64H2 supports PCI bus frequencies of 33 MHz and 66 MHz. For the PCI-X mode, the P64H2 supports PCI bus frequencies of 66 MHz, 100 MHz, and 133 MHz. Four PCI bus slots are supported at 33 MHz and 66 MHz, two slots are supported at 100 MHz, and one slot is supported at 133 MHz.
Read the full Intel® 82870P2 PCI/PCI-X 64-bit Hub 2 Datasheet.