
PM5317 SPECTRA-9953 Telecom Standard Product Data Sheet
Release
Proprietary and Confidential to PMC-Sierra, Inc., and for its customers’ internal use.
Document No.: PMC-2000741, Issue 5
514
18.4 System ACMP/DCMP Timing
Figure 39 shows the delay from DCMP/ACMP to the drop/add serial data links. DCMP/ACMP
is valid only at the DFP/AFP pulse time and are ignored at all other locations in the transport
frame. A change in value to the connection memory page signal (CMP) results in changing the
active space slot interchange settings. Given that CMP is sampled on the DFP/AFP pulse time 0,
the first data that is switched according to the newly selected connection memory page are the
A1 bytes of the second frame following the first J0 byte dropped/added by/to the SPECTRA-
9953. The time to the ASSI/DSSI page change is therefore afp/dfp_delay + 249.69 s.
Figure 39 CMP Functional Timing
DDP[
X
]/
DDN[
X
]
...
SYSCLK
DFP
S4,3/
A2
S1,1/J0
S2,1/
Z0
...
Valid
DCMP
X
X
Delay to J0
S1,1/
A1
S2,1/
A1
...
...
...
...
S3,1/
A1
Delay to second frame A1
249.69us
Connection page
is switched
18.5 Receive Transport Overhead Port Timing (RTOH)
The SPECTRA-9953 extracts and serially outputs all the transport overhead bytes (defined and
undefined) on the RTOH ports. 10368 bits (9x3x48 bytes) are output on each RTOH[N]
between two ROHFP assertion. Figure 40 shows the receive transport overhead (RTOH)
functional timings. ROHCLK[1:4] is a nominal 82.94MHz clock generated by gapping a
103.68MHz clock. The gapping occurs after the fourth bit 7 has been serialized out on the
RTOH port for each group of 4 bytes. This gap is eight 103.68 MHz clock periods wide. All
RTOH outputs (RTOH[N], ROHFP[N]) are updated on the rising edge of ROHCLK[N]. The
rising edge of ROHCLK[N] should be used to sample RTOH[N] and ROHFP[N]. Sampling
ROHFP[N] high identifies the MSB of the first A1 Byte on RTOH. It should be noted that
Figure 40 uses STS-1 ordering that is internal to SPECTRA-9953 and does not correspond
exactly to the Bellcore STS-1 ordering found in Figure 7.
When processing an STS-192/STM-64 or a quad STS-48/STM-16 data stream, the following
multiplexing structure is used :