PM7311 pmc-sierra, PM7311 Datasheet - Page 83

• Manufacturer Part Number: PM7311
• Description: Freedm 84a1024l Assp Telecom Standard Datasheet
• Manufacturer: pmc-sierra

Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2021832, Issue 2
next address is used to link to the start of the next datagram. The size field is used to indicate how
many of the data bytes are actually valid, as the last chunk may not be completely full. The abort
is used to trigger an HDLC abort. If an unexpected TSX error occurs during an Any-PHY transfer
or if the upstream device asserts the TERR signal, the abort is set.
The encapsulated data chunk, and an address pointer are passed to the DRAMC controller for
storage in external SDRAM. The address pointer is contained in the HDLC channel record and
points to the memory location that is placed in the next address pointer field of the previous data
chunk for a given datagram. The initial chunk of a datagram is stored at an address location,
(starting address of the datagram).
An address cache is used to hold addresses that can be used for next pointer values. When a
chunk is encapsulated, the HDLC channel record will fetch, from the local cache, another address
that can serve as the next address for the following data chunk in the datagram. The cache needs
to be replenished; this is achieved by requesting, from the DRAMC, a set of new addresses after a
threshold in the Cache has been crossed.
In order to preserve the address pointers in the presence of soft errors an ECC code is used to
detect 2 errors and correct 1 error.
Figure 26 Encapsulated Chunk Structure (Full = True)
Byte 1
Byte 7
Byte 13
Byte 19
Byte 25
Byte 31
Figure 27 Encapsulated Chunk Structure (Full = False)
Byte 0
Byte 6
Byte 12
Byte 18
Byte 24
Byte 30
Byte 0
Byte 6
Byte 12
Byte 18
Byte 24
Byte 30
Size
Byte 5
Byte 11
Byte 17
Byte 23
Byte 29
ECC(8)
Byte 5
Byte 11
Byte 17
Byte 23
Byte 29
ECC(8)
Byte 4
Byte 10
Byte 16
Byte 22
Byte 28
FREEDM 84A1024L ASSP Telecom Standard Product Data Sheet
Byte 10
Byte 16
Byte 22
Byte 28
Byte 9
Byte 15
Byte 21
Byte 27
L
Byte 4
L
Byte 3
F
F
A
A
00
00
NXT_CHUNK_PTR(19)
Byte 3
Byte 9
Byte 15
Byte 21
Byte 27
NXT_CHUNK_PTR(19)
Byte 2
Byte 8
Byte 14
Byte 20
Byte 26
Byte 2
Byte 8
Byte 14
Byte 20
Byte 26
Byte 1
Byte 7
Byte 13
Byte 19
Byte 25
Released
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