PM8621 PMC-Sierra, Inc., PM8621 Datasheet - Page 169

• Manufacturer Part Number: PM8621
• Description: NSE-8G Standard Product Data Sheet Preliminary
• Manufacturer: PMC-Sierra, Inc.

13.2
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2010850, Issue 1
Transmit Interface Timing
Figure 36 below shows the delay from assertion of RC1FP to the transmit serial data links. Due to
the presence of FIFOs in the data path, the delay to the various links can differ by up to eight
cycles. The minimum delay (RC1DLY + 43 SYSCLK cycles) is shown to be incurred by one of
the transmit protect serial data links (TP[X]/TN[X]). The maximum delay (RC1DLY + 51 cycles)
is shown to be incurred by one of the transmit auxiliary serial data links (TP[Y]/TN[Y]). The
suggested setting for TC1DLY results in a TC1FP pulse at the time at which all the transmit serial
links have transmitted their respective C1 characters. The maximum delay from RC1FP to the
transmission of a C1 pulse is RC1DLY + 52 cycles. Therefore the suggested setting for TC1DLY
is RC1DLY+ 52. Figure 36 shows the timing of TC1FP with the suggested setting for TC1DLY.
The relative phases of the links in Figure 36 are shown for illustrative purposes only. Links may
have different delays than what is shown.
Figure 37 Transmit Interface Timing
Figure 37 below shows the delay from CMP to the transmit serial data links. CMP is valid only at
the RC1FP pulse time, whether RC1FP is pulsed or not. It is ignored at other locations in the
transport frame. A change in value to the connection memory page signal (CMP) results in
changing the active switch settings. Given that CMP is sampled on the RC1FP pulse time, the
first data that is switched according to the newly selected connection memory page are the first
A1 bytes of the frame following the C1 bytes transmitted by the NSE-8G before offset RC1DLY
+ 52 cycles. In more absolute terms, the first A1s transmitted by the NSE-8G between offset
RC1DLY + 43 + 9696 cycles and RC1DLY + 51 + 9696 cycles, represent the first data switched
according the connection memory page selected by CMP at the RC1FP pulse time.
SYSCLK
RC1FP
TC1FP
TP[X]/
TN[X]
TN[Y]/
TP[Y]
RC1DLY + Min Delay(43
cycles) to First C1
TC1DLY (RC1DLY + Delay to TC1FP(52 cycles))
RC1DLY+ Max Delay(51 cycles) to Last C1
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S4,3/
A2
S1,1/J0
S2,1/
Z0
NSE-8G™ Standard Product Data Sheet
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S4,3/
A2
Preliminary
S1,1/
C1
168
S2,1/
Z0