ORT8850H AGERE [Agere Systems], ORT8850H Datasheet - Page 21

• Manufacturer Part Number: ORT8850H
• Description: Field-Programmable System Chip (FPSC) Eight-Channel x 850 Mbits/s Backplane Transceiver
• Manufacturer: AGERE [Agere Systems]

Data Sheet
August 2001
Backplane Transceiver Core Detailed
Description
Transport Overhead for In-Band Communication
The TOH byte can be used for in-band configuration,
service, and management since it is carried along the
same channel as data. In ORT8850, in-band signaling
can be efficiently utilized, since the total cost of over-
head is only 3.3%.
Transport Overhead Insertion (Serial Link)
The TOH serial links are used to insert TOH bytes into
the transmit data. The transmit TOH data and
TOH_CLK_EN get retimed by TOH_CLK in order to
meet setup and hold specifications of the device.
The retimed TOH data is shifted into a 288-bit (36-byte
by 8-bit) shift register and then multiplexed as an 8-bit
bus to be inserted into the byte-wide data stream.
Insertion from these serial links or pass-through of
TOH from the byte-wide data is under software control.
Transport Overhead Byte Ordering
(FPGA to Backplane)
In the transparent mode, SPE and TOH data received
on parallel input bus is transferred, unaltered, to the
serial LVDS output. However, B1 byte of STS#1 is
always replaced with a new calculated value (the
11 bytes following B1 are replaced with all zeros). Also,
A1 and A2 bytes of all STS-1s are always regenerated.
TOH serial port in not used in the transparent mode of
operation.
In the TOH insert mode, SPE bytes are transferred,
unaltered, from the input parallel bus to the serial LVDS
output. On the other hand, TOH bytes are received
from the serial input port and are inserted in the STS-
12 frame before being sent to the LVDS output.
Although all TOH bytes from the 12 STS-1s are trans-
ferred into the device from each serial port, not all of
them get inserted in the frame. There are three hard-
coded exceptions to the TOH byte insertion:
Agere Systems Inc.
Framing bytes (A1/A2 of all STS-1s) are not inserted
from the serial input bus. Instead, they can always be
regenerated.
Parity byte (B1 of STS#1) is not inserted from the
serial input bus. Instead, it is always recalculated
(the 11 bytes following B1 are replaced with all
zeros).
Pointer bytes (H1/H2/H3 of all STS-1s) are not
inserted from the serial input bus. Instead, they
always flow transparently from parallel input to LVDS
output.
(continued)
Eight-Channel x 850 Mbits/s Backplane Transceiver
In addition to the above hardcoded exceptions, the
source of some TOH bytes can be further controlled by
software. When configured to be in pass-through
mode, the specific bytes must flow transparently from
the parallel input. Note that blocks of 12 STS-1 bytes
forming an STS-12 are controlled as a whole. There
are 15 software controls per channel, as listed below:
TOH reconstruction is dependent on the transmitter
mode of operation. In the transparent mode, TOH
bytes on LVDS output are as shown in Table 2.
A new capability in the ORT8850 allows the user to
choose not to insert the B1 byte and the following
11 bytes of zeros. This option is also available for the
A1 and A2 bytes.
Source of K1 and K2 bytes of the 12 STS-1s
(24 bytes) is specified by a control bit (per channel
control).
Source of S1 and M0 bytes of the 12 STS-1s
(24 bytes) is specified by a control bit (per channel
control).
Source of E1, F1, E2 bytes of the STS-1s (36 bytes)
is specified by a control it (per channel control).
Source of D1 bytes of the STS-1s (12 bytes) is spec-
ified by a control bit (per channel control).
Source of D2 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
Source of D3 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
Source of D4 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
Source of D5 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
Source of D6 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
Source of D7 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
Source of D8 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
Source of D9 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
Source of D10 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
Source of D11 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
Source of D12 bytes of the 12 STS-1s (12 bytes) is
specified by a control bit (per channel control).
ORCA ORT8850 FPSC
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