PM5364 pmc-sierra, PM5364 Datasheet - Page 268

• Manufacturer Part Number: PM5364
• Description: Tupp 2488 Assp Telecom Standard
• Manufacturer: pmc-sierra

Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2011334, Issue 7
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The following section illustrates the path overhead bytes mapping on HTPOH when the STS-
12/STM4 frame carries:
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In the subsequent figures, each timeslot on the HTPOH signal represents 9 path overhead bytes.
STS-1/VC3
Figure 83 shows an STS-12/STM-4 data stream carrying 12 VC-3 payloads. The HTPOH
insertion opportunities are repeatedly assigned from STS-1/STM-0 #1 to #12 for 3 cycles in one
125 µs interval. As described in the previous section, a byte is inserted to the path overhead of
an outgoing data stream when HTPOHRDY is asserted and HTPOHEN is sampled high during
the most significant bit of the byte.
The HPOHFP signal provides synchronization between the HTPOH port and the transport
frame. It asserts high for 1 HPOHCLK clock cycle for every 125 µs. HPOHFP can be used
to identify the most significant bit of the first J1 byte for the first path on HTPOH.
During the path overhead insertion, the 9 path overhead bytes for each path are input on the
HTPOH pin, most significant bit first, in the same order that they are transmitted. 3 time
slots on HTPOH are assigned per path (total of 12 paths) per frame (125 µs). A maximum of
2 series of 864 bits (12x9 bytes) can be inserted on HTPOH between two HPOHFP
assertions. Hence, 0, 1, or 2 sets of path overhead per path per frame can be inserted to the
outgoing data streams.
The HTPOHRDY and HTPOHEN signals are used for handshaking between the external
device and the HTPOH port. When HTPOHRDY is asserted, the HTPOH port is ready to
receive path overhead bytes. If HTPOHRDY is asserted and HTPOHEN is sampled high on
the most significant bit of the byte, the byte will be inserted in the path overhead of the
outgoing data stream. If HTPOHRDY is asserted and HTPOHEN is sample low on the most
significant bit of the byte, the byte will not be inserted in the path overhead of the outgoing
data stream, and it will need to be reinserted at the next available opportunity.
12x STS-1s or 12x VC3s,
4x STS-3c or 4x VC-4/C-4s,
4x STS-3c or 4x VC-4/TUG-3s, and
1x STS-12c or 1x VC-4-4c.
Please note that when the egress traffic is an STS-48c/VC-4-16c data stream, only the first
of the 4 ports is used.
TUPP™ 2488 ASSP Telecom Standard Product Data Sheet
Released
268