xrt94l33 Exar Corporation, xrt94l33 Datasheet - Page 22

• 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.
G5
H6
TxTOHEnable
TxTOHClk
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
SONET/SDH O
O
O
CMOS
CMOS
VERHEAD
I
NTERFACE
Transmit TOH Input Port – Clock Output:
This
“TxTOHFrame” output pins and the “TxTOH” and “TxTOHIns”
input pins function as the “Transmit TOH Input Port”.
The Transmit TOH Input Port permits the user to externally
insert his/her own value(s) for the TOH bytes (within the
outbound STS-3/STM-1 signal).
This output pin provides the user with a clock signal. If the
“TxTOHEnable” output pin is “HIGH” and if the “TxTOHIns”
input pin is pulled “HIGH”, then the user is expected to provide
a given bit (within the “TOH”) to the “TxTOH” input pin, upon
the falling edge of this clock signal. The data, residing on the
“TxTOH” input pin will be latched into the XRT94L33 upon the
rising edge of this clock signal.
Note:
Transmit TOH Input Port – TOH Enable (or READY)
indicator:
This output pin, along with the “TxTOHClk”, “TxTOHFrame”
output pins and the “TxTOH” and “TxTOHIns” input pins
function as the “Transmit TOH Input Port”.
This output pin will toggle and remain “HIGH” anytime the
“Transmit TOH Input Port” is ready to externally accept TOH
data via the “TxOH” input pin.
To externally insert user values of TOH into the “outbound”
STS-3 data stream via the “Transmit TOH Input Port”, do the
following.
• Continuously sample the state of “TxTOHFrame” and this
output pin upon the rising edge of “TxTOHClk”.
• Whenever this output pin pulses “HIGH”, then the user’s
external circuitry should drive the “TxTOHIns” input pin
“HIGH”.
• Next, the user should output the next TOH bit, onto the
“TxTOH” input pin, upon the rising edge of “TxTOHClk”
22
output
The Transmit TOH Input Port only supports the
– T
insertion of the TOH within the very first STS-1 of the
outbound STS-3 signal.
RANSMIT
pin,
D
IRECTION
along
with
the
xr
“TxTOHEnable”,