Description:

VL82C592 (Host to PCI Bridge) data buffers.

The two data buffer chips are controlled by the 82C591. They provide the following basic capabilities:

• On host processor reads from system memory, the '591 reads the requested data from DRAM and instructs the '592 data buffers to pass it to the host data bus.

• On host processor writes to system memory, the '591 instructs the data buffers to accept the write data into the posted-write buffer. This permits the host processor to conclude the memory write quickly. The posted-write buffer then offloads the write data to DRAM memory.

• On PCI-initiated memory reads from system DRAM memory, the 82C591 reads the requested data from memory and instructs the 82C592 data buffers to pass it to the requester on the PCI data bus.

• On PCI-initiated memory writes to system DRAM memory, the 82C591 addresses memory and instructs the '592 data buffers to accept the data presented on the PCI data bus and route it into system DRAM.