xrt94l33 Exar Corporation, xrt94l33 Datasheet - Page 330

• 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.
Figure 76 A Simple Illustration of the “External Circuit” being interfaced to the “TxPOH Input Port”
Note:
•
“TxPOHEnable_n” pin “low”, then it should enter a “WAIT STATE” (e.g., where it waits for __ periods of
“TxPOHClk_n” to elapse). Afterwards, the external circuit should exit this “WAIT STATE” and then place the
very first bit (e.g., the most significant bit) of the “outbound” E2 byte onto the “TxPOH_n” input pin, upon the
very next falling edge of “TxPOHClk_n”. This data bit will be sampled and latched into the “Transmit STS-3c
POH Processor” block circuitry, upon the very next rising edge of “TxPOHClk_n”.
Note:
• Afterwards, the “external circuit” should serially place the remaining seven bits (of the E2 byte) onto the
“TxPOH_n” input pin, upon each of the next seven falling edges of “TxPOHClk_n”.
• The “external circuit” should then revert back to continuously sampling the states of the “TxPOHEnable_n”
and “TxPOHFrame_n” output pins and repeat the above-mentioned process.
Figure 77 presents an illustration of the “TxPOH Input Interface” waveforms, when the “external circuit” is
writing the E2 byte into the “TxPOH Input Port”.
Figure 77 Illustration of the “TxPOH Input Interface” waveforms, when the “External Circuit” is writing
the “E2 byte” into the “TxPOH Input Port”.
Whenever the “external circuit” samples the “TxPOHFrame_n” output pin “high” and also the
The “TxPOHIns_n” line (inFigure 76) is “dashed” because this controlling this signal is not necessary if the user
This “WAIT STATE” period is necessary because the E2 byte is the _ byte within the TOH.
has executed “STEP 2” above.
XRT94L43 Device
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
TxPOHEnable_n
TxPOHFrame_n
TxPOHClk_n
TxPOHIns_n
TxPOH_n
330
TxPOHData_OUT
TxPOHFrame_IN
TxPOHEnable_IN
TxPOH_INSERT
TxPOHClk_IN
External Circuit
xr