Nortel Networks 1000 - Manual (Page 857)

Functional description 857
The microprocessors also handle some D-channel data processing in
DCHI mode.
One microprocessor handles data transfer between each pair of serial
ports and software, reports the status of each port and takes commands
from software to control the activities of the ports. The microprocessors
also do some of D-channel data processing in DCHI mode.
One microprocessor does the following:
• handles data transfer between each pair of serial ports and software
•
reports the status of each port
• takes commands from software to control the activities of the ports
The microprocessors also handle some D-channel data processing in
DCHI mode.
DMA controller
A Z80A-DMA chip controls the data transfer between local RAM memory
and communication ports. The DMA channels are only used in the receive
direction (from line to SSC), not in the transmit direction.
A Z80A-DMA chip controls the data transfer between local RAM memory
and communication ports. Note that the DMA channels are only used in
the receive direction (from line to CPU), not in the transmit direction.
A Z80A-DMA chip controls the data transfer between local RAM memory
and communication ports. The DMA channels are only used in the receive
direction (from line to SSC), not in the transmit direction.
Random Access Memory (RAM)
A total of 32 KBytes of RAM space for each pair of ports is used as the
communication buffer and for firmware data storage.
A total of 32K bytes of RAM space for each pair of ports is used as the
communication buffer and firmware data storage.
A total of 32 kbytes of RAM space for each pair of ports is used as the
communication buffer and for firmware data storage.
Read Only Memory (ROM)
A total of 32K bytes of ROM space for each pair of ports is reserved as a
code section of the DCH-PORT firmware.
A total of 32K bytes of ROM space for each pair of ports is reserved as a
code section of the DCH-PORT firmware.
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 02.06 Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.