RELEASED
PM7380 FREEDM-32P672
DATA SHEET
PMC-1990262
ISSUE 5
FRAME ENGINE AND DATA LINK MANAGER 32P672
Field
Description
CE
The Chain End (CE) bit is used by the host to indicate
the end of a linked list of TDs presented to the
TMAC672. The linked list can contain one or more
packets as delineated by the M bit (see above).
When CE is set to logic 1, the current TD is the last
TD of a linked list of TDs. When CE is set to logic 0,
the current TD is not the last TD of a linked list.
When the current TD is not the last of the linked list,
the Host Next TD Pointer[14:0] field is valid,
otherwise the field is not valid.
Note: When CE is set to logic 1, the only valid value
for M is logic 0.
Note: When presenting raw (i.e. unpacketised) data
for transmission, the host should code the M and CE
bits as for a single packet chain, i.e. M=1, CE=0 for
all TDs except the last in the chain and M=0, CE=1
for the last TD in the chain.
TCC[9:0]
V
The Transmit Channel Code (TCC[9:0]) bits are used
by the host to associate a channel with a TD pointed
to by a TDR.
All TCC[9:0] fields in a linked list of TDs must be set
to the same value.
The V bit is used to indicate that the TMAC Next TD
Pointer field is valid. When set to logic 1, the TMAC
Next TD Pointer[14:0] field is valid. When V is set to
logic 0, the TMAC Next TD Pointer[14:0] field is
invalid. The V bit is used by the host to reclaim data
buffers in the event that data presented to the
TMAC672 is returned to the host due to a channel
becoming unprovisioned. The V bit is expected to be
initialised to logic 0 by the host.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA,INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
66
PMC [ PMC-SIERRA, INC ]
