Service Manual

GSM-205-323
MCUF
31st Oct 01
Technical Description: Horizon macro indoor
68P02902W07-B
CONTROLLED INTRODUCTION
Tech. 6–9
PIX interfaces
The MCUF provides four PIX outputs on the backplane, driven at V. 28 levels.
The four PIX outputs, routed to the cabinet alarm board, enable relay contact
control of external customer equipment.
DRAM, flash
EPROM and
code loading
functions
DRAM
The 16 Mbyte DRAM provides operational code and data storage for the main
processors. There is also a SIMM socket in the circuit board, enabling the
addition of a further 16 Mbytes if required. After software initialization, the DRAM
uses ECC protection. Memory protection is provided by the main processors.
Fast flash EPROM
The fast flash 1 Mbyte bank is used for bootcode and executive process code. It
has a fast access time (<75 ns), enabling direct execution. The bootcode is
factory set, and reprogrammed only in major software upgrades.
Slow flash EPROM
The slow flash 0.5 Mbyte bank is used for non-volatile data storage of diagnostic
data and module ID information.
Code loading
The boot and executive code, held in the fast flash EPROM, initiates the MCUF
on power up or reset. If a PCMCIA memory card is fitted, operational code may
be obtained and copied to the DRAM for execution. If no card or code is
available, the operational code is obtained from the BSC.
Before execution, the operational code held in DRAM is checked with code held
at the BSC. The BSC downloads any changed code objects to the DRAM.
After successful checking of the DRAM operational code, the code is executed,
and the PCMCIA memory card updated with any changed objects.
CSFP code loading
If a PCMCIA memory card is available,then a code storage facility processor
(CSFP) function can be supported. A new software load can be downloaded in
the background, without any reduction in service, and stored on the PCMCIA
card.
Once the complete load has been transferred to the PCMCIA card, a code swap
can be initiated. The site is reset and the new software brought into service (<10
minutes). As a precaution, the old version is held on the PCMCIA card to
support a roll back to the original version if required.