Nortel Circuit Card 311 Reference page 957

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:
•
•
•
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.
Copyright © 2003-2008, Nortel Networks
.
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
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311 01.04 Standard
Release 5.0 23 May 2008
Functional description 957