1-8
1.4
System Architecture
Alpha microprocessor chips are used in these systems. The CPU, memory, and
the I/O module(s) are connected to the system motherboard.
Figure 1-4 Architecture Diagram
XBUS
Xceivers
I2C Bus
Interface
Mouse/
Keyboard
Combo I/O:
serial ports
parallel port
floppy cntrl
Real-Time
Clock
BDATA
Xceivers
XBUS
EISA
Bus
PKW0502-97
PCI Bus 1
System Bus
Memory
Pair
CPU
PCI Slot
PCI Slot
PCI Bus 0
System to
PCI Bus
Bridge 0
IOD0
System to
PCI Bus
Bridge 1
IOD1
PCI Slot
PCI Slot
EISA
Bridge
PCI Slot
PCI Slot
EISA Slot
128-Bit Data Bus + 16 ECC and 40-Bit Command/Address Bus
64 Bits
64 Bits
System
Motherboard
Flash
ROM
2MB
NVRAM
8Kx8
Note: When the ISA slot on
PCI Bus 0 is used, the last
PCI slot on PCI Bus 1 is not
available.