2-2 Functional Description
Figure 2.1 LSI53C875A Block Diagram
2.1 PCI Functional Description
The LSI53C875A implementsa PCI-to-Wide Ultra SCSI controller.

2.1.1 PCI Addressing

There are three physical PCI-defined address spaces:
PCI Configuration space.
I/O space for operating registers.
Memory space for operating registers.
32Bit PCI Interface, PCI Configuration Register
4Kbyte
SCRIPTS RAM 8Dword SCRIPTS
PrefetchBuffer
944byte
DMAFIFO SCSISCRIPTS
Processor Operating
Registers
ROM/Flash SerialEEPROM
Local
Memory
Bus
SCSIFIFO and SCSI Control Block
SETolerANT
Driversand Receivers
JTAG
PCIBus
JTAGBus WideUltra
SCSIBu s ROM/Flash
MemoryBus 2-Wir e Serial
EEPROMBus
WideUltra SCSI Controller
Controllerand
Autoconfiguration
Memory
Control