Service manual

Firmware Updates D-17
Once the SCM completes the map of the CSB, LFU provides the updated
XSROM code to the SCM through shared RAM. The SCM sends the code
to the PSM in each QBB. After the PSM receives the code, it then blasts it
into the XSROM flash ROM.
LFU provides code for the HPM to the SCM. The SCM downloads this code
over the CSB to the HPM in the H-switch.
11
LFU then provides code for the PSMs to the SCM. The SCM downloads
this code over the CSB to RAM space in each PSM. If there were more
than one QBB on the system the download to each is done in parallel. Note
that the code is not yet written into the PSM’s flash ROM from which it
runs.
12
Next LFU provides new code for the PBMs to the SCM. The SCM
downloads this code over the CSB to RAM space controlled by PBMs on
each PCI backplane at CSB nodes 10 and 11. Again note that the code is
not yet written into the PBM’s flash ROM from which it runs.
13
When the LFU finishes updating all the micros, LFU sends a last packet to
the SCM which causes the SCM to issue commands to each PSM and each
PBM to transfer the new firmware code each has stored in its RAM to their
respective flash ROMs.