PM5381-BI PMC-Sierra, Inc., PM5381-BI Datasheet - Page 98

• Manufacturer Part Number: PM5381-BI
• Description: ATM UNI, Single Channel ATM PHY Interface for 2488.32Mbps
• Manufacturer: PMC-Sierra, Inc.

Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2000489, Issue 4
The TRMP accumulates the line BIP-8 errors detected by the RRMP during the last receive
frame. The line BIP-8 errors are returned to the far end as line remote error indication (REI-L)
during the next transmit frame. Because the RRMP and the TRMP are in two different clock
domains, none, one or two line BIP-8 errors can be accumulated per transmit frame. The
minimum value between the maximum REI-L and the accumulator count is returned as the line
REI-L in the M1 byte of STS-1 (STM-0) #3. Optionally, block BIP-24 errors can be
accumulated. For STS-48c (STM-16c), the maximum single BIP-8 error count is 0xFF while the
maximum block BIP-24 error count is 0x10.
The TRMP serially inputs all the transport overhead (TOH) bytes from the TTOH port. The TOH
bytes must be input in the same order that they are transmitted (A1, A2, J0/Z0, B1, E1, F1, D1-
D3, H1-H3, B2, K1, K2, D4-D12, S1/Z1, Z2/M1/Z2 and E2). TTOHCLK is the generated output
clock used to provide timing for the TTOH port. TTOHCLK is a nominal 20.736 MHz clock
generated by gapping a 25.92 MHz clock. Sampling TTOHFP high with the rising edge of
TTOHCLK identifies the MSB of the first A1 byte. TTOHEN port is used to validate the byte
insertion on a byte per byte basis. When TTOHEN is sampled high on the MSB of the serial
byte, the serial byte is inserted. When TTOHEN is sampled low on the MSB of the serial byte,
the serial byte is discarded.
Figure 18 STS-48c (STM-16-16c) On TTOH
Note, only the overhead from the first STS-12 (STM-4) of the STS-48c (STM-16c) can be
sourced. Overhead from the other three STS-12s (STM-4s) are internally generated assigned or
are assigned default values as described below.
The TRMP also inserts most of the transport overhead bytes from internal registers. Since there
are multiple sources for the same overhead byte, the TOH bytes must be prioritized according to
Table 4 before being inserted into the data stream.
D10
First order of transmission
A1
B1
D1
H1
B2
D4
D7
S1
Unused bytes
A1 A1
H1
B2
Z1
H1
B2
Z1
A1
H1
B2
Z1
National bytes
A1
H1
B2
Z1
...
...
...
...
...
...
...
...
...
Z0 Z0 or National bytes
H1
A1
B2
Z1
D11
D2
H2
D5
D8
A2 A2
E1
K1
Z2
H2
Z2
H2
M1
A2
H2
A2
Z2
H2
A2
Z2
S/UNI-2488 Telecom Standard Product Datasheet
...
...
...
...
...
...
...
...
...
H2
A2
Z2
D12
D3
H3
D6
D9
F1
K2
E2
J0
H3
Z0
H3
Z0
H3
Z0
H3
Z0
...
...
...
...
...
...
...
...
...
Z0
H3
Released
98