
DATA SHEET
PM7367 FREEDM-32P32
ISSUE 2
PMC-1991499
FRAME ENGINE AND DATA LINK MANAGER
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMER’S INTERNAL USE
38
Field
RCC[6:0]
Description
The Receive Channel Code (RCC[6:0]) bits are used by
the RMAC to indicate which channel an RPD is
associated with. Legal values for this field are 0 to 31.
For a linked list of RPDs, all the RPDs’ RCC fields are
valid, i.e. all contain the same channel value.
CE
The Chain End (CE) bit indicates the end of a linked list of
RPDs. When CE is set to logic one, the current RPD is
the last RPD of a linked list of RPDs. When CE is set to
logic zero, the current RPD is not the last RPD of a linked
list.
The CE bit is valid for all RPDs written by the RMAC to
the Receive Ready Queue. When a packet requires only
one RPD, the CE bit is set to logic one. The CE bit is
ignored for all RPDs read by the RMAC from the Receive
Free Queues, each of which is assumed to point to only
one buffer, i.e. not a chain.
Offset[1:0]
The Offset[1:0] bits indicate the byte offset of the data
packet from the start of the buffer. If this value is non-
zero, there will be ‘dummy’ (i.e. undefined) bytes at the
start of the data buffer prior to the packet data proper.
For a linked list of RPDs, only the first RPD's Offset field
is valid. All other RPD Offset fields of the linked list are
set to 0.
Status [5:0]
The Status[5:0] bits indicate the status of the received
packet.
Status[0] Rx buffer overrun
Status[1] Packet exceeds max. allowed size
Status[2] CRC error
Status[3] Packet Length not an exact no. of bytes
Status[4] HDLC abort detected
Status[5] Unused (set to 0)
For a linked list of RPDs, only the last RPD's Status field
is valid. All other RPD Status fields of the linked list are
invalid and should be ignored. When a packet requires
only one RPD, the Status field is valid.