PM5381-BI PMC-Sierra, Inc., PM5381-BI Datasheet - Page 57

• 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
Pin Name
TTOH
TTOHEN
TPOH
Type
Input
Input
Input
Pin
No.
AK27
AJ26
AH25
Function
The transmit transport overhead (TTOH) signal contains all
transport overhead bytes (A1, A2, J0, Z0, B1, E1, F1, D1-D3,
H1-H3, B2, K1, K2, D4-D12, Z1/S1, Z2/M1, E2, and all
undefined transport overhead) to be transmitted and the error
masks to be applied on B1, B2, H1 and H2. Transport
overhead can only be inserted into the first STS-12 slice in
this manner. TTOH should be grounded if it is not used.
TTOH is sampled on the rising edge of TOHCLK.
The transmit transport overhead insert enable (TTOHEN)
signal controls the insertion of the transmit transport overhead
data which is inserted in the outgoing stream.
When TTOHEN is high during the most significant bit of a
TOH byte on TTOH, the sampled TOH byte is inserted into
the corresponding transport overhead byte positions (A1, A2,
J0, Z0, E1, F1, D1-D3, H3, K1, K2, D4-D12, Z1/S1, Z2/M1,
E2, and all undefined transport overhead bytes). When
TTOHEN is low during the most significant bit of a TOH byte
on TTOH, that sampled byte is ignored and the default values
are inserted into these transport overhead bytes.
When TTOHEN is high during the most significant bit of the
H1, H2, B1 or B2 TOH byte positions on TTOH, the sampled
TOH byte is logically XORed with the associated incoming
byte to force bit errors on the outgoing byte. A logic low bit in
the TTOH byte allows the incoming bit to go through while a
bit set to logic high will toggle the outgoing bit. A low level on
TTOHEN during the MSB of the TOH byte disables the error
forcing for the entire byte.
TTOHEN should be grounded if it is not used.
Transport overhead can only be inserted into the first STS-12
slice in this manner. TTOHEN is sampled on the rising edge
of TOHCLK.
The transmit path overhead (TPOH) signal contains the
path overhead bytes (J1, C2, G1, F2, Z3, Z4, and Z5) to be
transmitted in the STS-48c SONET path overhead and the
error masks to be applied on B3 and H4. Path overhead can
only be inserted within the first STS-12 slice in this manner.
A path overhead byte is accepted for transmission when the
external source indicates a valid byte (TPOHEN set high) and
the S/UNI-2488 indicates ready (TPOHRDY set high). The
S/UNI-2488 will ignore the byte on TPOH when TPOHEN is
set low. The TPOHRDY is set low to indicate that the S/UNI-
2488 is not ready and the byte must be re-presented at the
next opportunity.
TPOH should be grounded if it is not used.
TPOH is sampled on the rising edge of TOHCLK.
S/UNI-2488 Telecom Standard Product Datasheet
Released
57