Nortel DMS-100 Series Maintenance Manual page 20

1-8 Maintenance overview
The NT6X51BA card contains two banks of FLASH ROM memory. Each
bank can hold up to 4M of software and data. The NT6X51BA also
contains a 2M bank of DRAM (Dynamic RAM). FLASH ROM devices can
be reprogrammed multiple times. The two banks of FLASH ROM are
configured so that only one FLASH ROM bank is active at any one time.
An electrically erasable potentiometer (EEPOT) determines which bank is
active. The logic on the board does not allow the active bank to be erased or
reprogrammed. Only the standby bank can be erased and reprogrammed.
This allows the RLCM-EDC to be downloaded while in service. As seen in
the following diagram
NT6X51BA processor configuration
CM
CP circuit resources The CP transfers message packets from the DMS host
carried by C-side message links to the MP. The CP uses the HDLC (LAPD
Q.921) protocol for the C-side message channel. Bus accesses into the DCC
are arbitrated between the MP and CP processors since there is only one
processor bus interface implemented on the NT6X52 DCC pack.
PP circuit resources The PP transfers message packets from line drawer
bus interface card (BIC) circuits across receiver control (RCON) and
transmit control (TCON) serial message links.
Miscellaneous hardware resources The NT6X51BA card contains the
following miscellaneous hardware functions that are not part of any
processor circuit:
297-8381-550 Standard 02.02 April 1999
4M Active
Flash
Debug
port
Dual-port
RAM
C-side processor
256k SRAM
power rail input circuit
4M Standby
EEPOT
Flash
Main processor
2M DRAM
Serial link
IUC link
Dual-port
RAM
P-side processor
256k SRAM
BIC
and
LC