xrt94l33 Exar Corporation, xrt94l33 Datasheet - Page 34

• Manufacturer Part Number: xrt94l33
• Description: Multi-channel, Multi-function Device Aggregates 3 Ds3/e3/sts-1 Into Oc3/stm-1
• Manufacturer: Exar Corporation

XRT94L33
Rev.1.2.0.
AC16
D12
C18
TxOHENABLE_0
TxOHENABLE_1
TxOHENABLE_2
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
O
CMOS
Transmit Overhead Enable Output indicator
This output pin functions as the “Transmit Overhead Enable”
output indicator for the transmit system side interface when the
XRT94L33 is configured to operate in STS-1/DS3/E3 mode,
however, it functions as the “Transmit STS-1 Overhead
Enable” output when the device is configured to operate in the
STS-1 mode.
When configured to operate in DS3/E3 mode:
The Channel will assert this output pin, for one “TxInClk”
period, just prior to the instant that the Transmit Overhead
Data Input Interface will be sampling and processing an
overhead bit.
If the local terminal equipment intends to insert its own value
for an overhead bit, into the outbound DS3 or E3 data stream,
then it is expected to sample the state of this signal, upon the
falling edge of “TxInClk”. Upon sampling the “TxOHEnable_n”
signal high, the local terminal equipment should (1) place the
desired value of the overhead bit, onto the “TxOH_n” input pin
and (2) assert the “TxOHIns_n” input pin.
Overhead Data Input Interface block will sample and latch the
data on the “TxOH_n” signal, upon the rising edge of the very
next “TxInClk_n” input signal.
When configured to operate in STS-1 mode:
These output pins, along with “TxOH_n”, “TxOHIns_n”,
“TxOHFrame_n” and “TxOHClk_n” function as the “Transmit
Path Overhead (TxOH) Input Port”.
These output pins will pulse “high” anytime the “TxOH” port is
ready to accept and process POH bytes.
will be “low” at all other times.
34
xr
These output pins
The Transmit