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XRT94L43
312
REV. 1.0.2
SONET/SDH OC-12 TO 12XDS3/E3 MAPPER
NOTE: The values for t18, t19 and t20 can be found in Table 18. 8.0
TRANSMIT ORDERWIRE (E1, F1, E2) BYTE OVERHEAD INPUT PORT
8.1
Transmit E1, F1, E2 (Order-wire) Byte Overhead Input Port
The Transmit Order-wire Byte Overhead Input Port provides a dedicated port for the user to insert his/her own
value for the E1, F1 and E2 bytes within the outbound STS-12/STM-4 data-stream. The user should note that
the TxE1F1E2 input pin is sampled (by the Transmit Order-wire Byte Overhead Input Port) upon the rising
edge of TxTOHClk. All of the remaining signals (e.g., TxE1F1E2Enable, TxE1F1E2Frame) are updated upon
the falling edge of TxTOHClk.
The timing waveform and information for the Transmit Order-wire Byte
Overhead Input Port is presented below.
FIGURE 23. TIMING WAVEFORM OF THE TRANSMIT POH OVERHEAD INPUT PORT
TABLE 18: TIMING INFORMATION FOR THE TRANSMIT POH OVERHEAD INPUT PORT
SYMBOL
DESCRIPTION
MIN.
TYP.
MAX.
t18
Falling edge of TxPOHClk to rising edge of TxPOHFrame and
TxPOHEnable
-1.5ns
3ns
t19
TxPOHIns to rising edge of TxPOHClk set-up time
15ns
t20
TxPOH Data to rising edge of TxPOHClk set-up time
14ns
TxPO H
TxPO HIns
T xPO HClk
TxPO HFram e
TxPO HEnable
t
18
t
19
t
20