PM5342 SPECTRA-155
DATA SHEET
PMC-970133
ISSUE 4
SONET/SDH PAYLOAD EXTRACTOR/ALIGNER
Register 1CH: SPECTRA-155 Overhead Unused Bytes Control
Bit
Type
R/W
R/W
R/W
R/W
Function
UNUSED_EN
UNUSED_V
NAT_EN
NAT_V
Default
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0
0
0
0
Unused
Unused
Unused
Unused
X
X
X
X
NAT_V:
The NAT_V bit determines the value of the national use transport overhead
bytes when overwrite is enabled using the NAT_EN bit. When NAT_V is set
high, the national use transport overhead bytes are set to FFH. When
NAT_V is set low, the national use transport overhead bytes are set to 00H.
Please refer to the NAT_EN bit description for the list of national use bytes
affected.
NAT_EN:
The NAT_EN bit enables overwriting the national use transport overhead
bytes with an all ones or all zeros pattern. When NAT_EN is set high, the F1
#2 (S{2,8,1}), F1 #3 (S{2,9,1}), the E2 #2 (S{9,8,1}) and E2 #3 (S{9,9,1})
bytes are overwritten with an all ones pattern or all zeros pattern as controlled
by the NAT_V bit. When NAT_EN is set low, the national use transport
overhead bytes are controlled by the TTOHEN input and the TLOP block.
When NAT_EN and TTOHEN are both high, the NAT_EN has precedence.
Note, national use bytes Z0 #2 (S{1,8,1}) and Z0 #3 (S{1,9,1}) are not
affected by the NAT_EN bit. These bytes can be controlled using the Z0INS
bit in the SPECTRA-155 Section/Line Control/Enable register.
UNUSED_V:
The UNUSED_V bit determines the value of the unused transport overhead
bytes when overwrite is enabled using the UNUSED_EN bit. When
UNUSED_V is set high, the unused transport overhead bytes are set to FFH.
When UNUSED_V is set low, the unused transport overhead bytes are set to
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
185
PMC [ PMC-SIERRA, INC ]
