Maintenance Bus (I 2 C Bus); C Bus Block Diagram - Compaq AlphaServer DS20 Service Manual

1.14 Maintenance Bus (I
2
There are two I C buses (referred to as the "I squared C bus") in this system.
The internal maintenance bus is used to monitor system conditions scanned by
the power control logic on the server feature module, log error state and track
system configuration information. There is a private I
and the C-chip used to provide memory configuration information to the consoles
and operating systems.
2
Figure 1-19 I

C Bus Block Diagram

Server Feature
Module
NVRAM
PCL
Registers
1
Thermom/
Thermostat
CPU 0
System
Board
OCP
Controller
2
I C Bus
1-36 AlphaServer DS20 Service Manual
2
C Bus)
2
C bus between memory
C-Chip
Private
2
I C Bus
up to 4
Memory
Banks
2
I C Bus
XBUS
Controller
System
P-Chip 0
ISA Bridge
PK1406-99