PM7384 FREEDM-84P672
DATA SHEET
PMC-1990445
ISSUE 5
FRAME ENGINE AND DATA LINK MANAGER 84P672
FLEN[10:0]:
The indirect FIFO length (FLEN[10:0]) is the number of blocks, less one, that
is provisioned to the circular channel FIFO specified by the FPTR[10:0] block
pointer. The FIFO length to be written to the channel provision RAM, in an
indirect channel write operation, must be set up in this register before
triggering the write.
Reserved:
The reserved bit must be set low for correct operation of the FREEDM-
84P672 device.
DFCS:
The diagnose frame check sequence bit (DFCS) controls the inversion of the
FCS field inserted into the transmit packet. The value of DFCS to be written
to the channel provision RAM, in an indirect channel write operation, must be
set up in this register before triggering the write. When DFCS is set to one,
the FCS field in the outgoing HDLC stream is logically inverted allowing
diagnosis of downstream FCS verification logic. The outgoing FCS field is
not inverted when DFCS is set to zero. DFCS reflects the value written until
the completion of a subsequent indirect channel read operation.
INVERT:
The HDLC data inversion bit (INVERT) configures the HDLC processor to
logically invert the outgoing HDLC stream. The value of INVERT to be written
to the channel provision RAM, in an indirect channel write operation, must be
set up in this register before triggering the write. When INVERT is set to one,
the outgoing HDLC stream is logically inverted. The outgoing HDLC stream
is not inverted when INVERT is set to zero. INVERT reflects the value written
until the completion of a subsequent indirect channel read operation.
PRIORITYB:
The active low channel FIFO starving enable bit (PRIORITYB) informs the
partial packet processor of the priority of the channel relative to other
channels when requesting data from the DMA port. The value of PRIORITYB
to be written to the channel provision RAM, in an indirect channel write
operation, must be set up in this register before triggering the write. Channel
FIFOs with PRIORITYB set to one are inhibited from making expedited
requests for data to the TMAC672. When PRIORITYB is set to zero, both
normal and expedited requests can be made to the TMAC672. Channels
with HDLC data rate to FIFO size ratio that is significantly lower than other
channels should have PRIORITYB set to one. PRIORITYB reflects the value
written until the completion of a subsequent indirect channel read operation.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
227
PMC [ PMC-SIERRA, INC ]
