xrt94l33 Exar Corporation, xrt94l33 Datasheet - Page 24

• 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.
D6
TxTOHIns
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
I
TTL
Transmit TOH Input Port – Insert Enable Input pin:
This input pin, along with the “TxTOH” input pin, and the
“TxTOHEnable”, “TxTOHFrame” and “TxTOHClk” output pins
function as the “Transmit TOH Input Port”.
This input pin permits the user to either enable or disable the
“Transmit TOH Input Port”.
If this input pin is “LOW”, then the “Transmit TOH Input Port”
will be disabled and will not sample and insert (into the
“outbound” STS-3 data stream) any data residing on the
“TxTOH” input, upon the rising edge of “TxTOHClk”
If this input pin is “HIGH”, then the “Transmit TOH Input Port”
will be enabled. In this mode, whenever the “TxTOHEnable”
output pin is also “HIGH”, the “Transmit TOH Input Port” will
sample and latch any data that is presented on the “TxTOH”
input pin, upon the rising edge of “TxTOHClk”.
To externally insert user values of TOH into the “outbound”
STS-3 data stream via the “Transmit TOH Input Port”, do the
following.
•
“TxTOHEnable” upon the rising edge of “TxTOHClk”.
• Whenever the “TxTOHEnable” output pin is sampled “high”
then the user’s external circuitry should drive this input pin
“HIGH”.
• Next, the user should output the next TOH bit, onto the
“TxTOH” input pin, upon the falling edge of “TxTOHClk”. The
“Transmit TOH Input Port” will sample the data (on this input
pin) upon the falling edge of “TxTOHClk”.]
Notes:
1.
2.
3. For other TOH bytes, “TxTOH” input pin will be sampled if
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Continuously sample the state of “TxTOHFrame” and
Data applied to the “TxTOH” input pin will be sampled
according to the following insertion priority scheme:
For DCC, E1, F1, E2 bytes, “TxTOH” input pin will be
sampled if both “TxTOHEnable” and “TxTOHIns” are high.
both “TxTOHEnable” and “TxTOHIns” are high or if both
“TxTOHIns” and “Software Insertion Enabled” are “low”.
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