HP 520 5/XX, 525 5/XX manual 62

3 System Board (P/Ns D3657-63001 and D3661-63001)

Principal Components and Features

Principal Components and Features

PCI Chipset

The PCI chipset consists of four chips that interface between the three main buses (the processor’s local (PL) bus, the PCI bus, and the ISA bus):

•The PL/PCI bridge chip (SB82437FX-66) which also provides control for the PCI bus, level-2 cache memory, and main memory.

•Two data path unit chips (SB82438FX) that provide a 64-bit data path between the processor local bus and main memory modules.

•The PCI/ISA bridge chip (SB82371FB) also provides control for the IDE.

Host Bus PCI Bus ISA Bus

SB82438FX

Data Path Unit

Pentium									SB82371FB
		SB82438FX						PCI/ISA Bridge
Processor
	Data Path Unit							PCI
								Master			ISA Bus
											Controller
								PCI
							Main	Slave
							Memory
								APIC			IDE
		Level-Two									Controller
			Cache
										BIOS
			SB82437FX-66 PCI, Cache
			and Memory Controller
			Cache			Main
			Controller
						Memory
			Write		Controller
			Buffer
				PCI			PCI
			Master			Slave

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