Compaq GS160 - Manual (Page 32)

2-14 AlphaServer GS80/160/320 User's Guide
2.3.6 Power System Manager Module
Each QBB has one power system manager (PSM) module. This module
monitors CPUs, voltages, temperatures, and blower speed in the
cabinet and reports this information to the system control manager
(SCM).
Figure 2–10 Power System Manager Module
PK0607
The PSM module is connected to other PSM modules and the SCM micro-
processor (located on the standard I/O module) through the console serial bus
(CSB). The SCM is the master; the PSM can only operate as a slave. The PSM
controls the powering on/off and resetting of all modules within the QBB and of
the QBB itself. The PSM also contains three I
2 C bus interfaces and a serial I/O
bus channel to each CPU in the QBB. The PSM module retrieves information
from the I
2 C EEROMs residing on the CPUs, memory modules, and the QBB
backplane. The PSM uses a serial I/O port connection to communicate with one
CPU module at a time. The PSM can only perform a function as the result of a
request from the SCM.