RELEASED
PM7380 FREEDM-32P672
DATA SHEET
PMC-1990262
ISSUE 5
FRAME ENGINE AND DATA LINK MANAGER 32P672
XFER[3:0]:
The indirect channel transfer size (XFER[3:0]) configures the amount of data
transferred in each transaction. The channel transfer size to be written to the
channel provision RAM, in an indirect write operation, must be set up in this
register before triggering the write. When the channel FIFO depth reaches
the depth specified by XFER[3:0] or when an end-of-packet exists in the
FIFO, a request will be made to the RMAC672 to initiate a PCI write access
to transfer the data to the PCI host. Channel transfer size is measured in 16
byte blocks. The amount of data transferred and the depth threshold are
specified by given setting is:
XFER[3:0] + 1 blocks = 16 * (XFER[3:0] + 1) bytes
XFER[3:0] should be set such that the number of blocks transferred is at
least two fewer than the total allocated to the associated channel. XFER[3:0]
reflects the value written until the completion of a subsequent indirect channel
read operation.
OFFSET[1:0]:
The packet byte offset (OFFSET[1:0]) configures the partial packet processor
to insert invalid bytes at the beginning of a packet stored in the channel FIFO.
The value of OFFSET[1:0] 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. The number of bytes inserted before the beginning of a
HDLC packet is defined by the binary value of OFFSET[1:0]. OFFSET[1:0]
reflects the value written until the completion of a subsequent indirect channel
read operation.
CRC[1:0]:
The CRC algorithm bits (CRC[1:0]) configures the HDLC processor to
perform CRC verification on the incoming data stream. The value of
CRC[1:0] 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.
CRC[1:0] is ignored when DELIN is low. CRC[1:0] reflects the value written
until the completion of a subsequent indirect channel read operation.
Table 18 – CRC[1:0] Settings
CRC[1]
CRC[0]
Operation
0
0
1
0
1
0
No Verification
CRC-CCITT
CRC-32
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA,INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
139
PMC [ PMC-SIERRA, INC ]
