Digital Equipment Prioris XL 6000 Series, Service Maintenance Manual, Page: 174 / 174

Block Diagram
E-9
PRIO
RIS
XL
6000
PCI Bus
The Peripheral Component Interconnect (PCI) bus provides three physical address
spaces:
•
32-bit memory
•
32-bit I/O
•
256 byte-per-agent configuration space.
The PCI bus supports 8-bit, 16-bit, and 32-bit data transfers at a bus clock speed of
30 or 33 MHz depending on CPU speed. This allows 32-bit data transfers at 120 MB
per second.
The MLB has three PCI slots. Bus mastering is supported on all three PCI slots.
System Management Blocks
The lower part of Figure E-1 shows several blocks for system management
resources on an IIC bus (also called I
2
C bus): An 8031 subsystem detects such
items as fan failure; an ADC/DAC 8591 detector monitors voltages and temperature
sensors, include the temperature of the two CPUs; and a Watchdog timer monitors
dc power and turns off system power if necessary. The 8031 has an external
EEPROM so that resources can be accessed, detected, or changed by software. A
management software package, such as ServerWORKS Manager, can be used to
manage all these system resources.