xrt94l33 Exar Corporation, xrt94l33 Datasheet - Page 248

• 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.
STEP 1 – Write the value “1” into Bit 0 (Z4 Byte Insertion Type) within the “Transmit STS-3c Path –
SONET Control Register – Byte 1”, as depicted below.
Transmit STS-3c Path – SONET Control Register – Byte 1 (Address = 0x1982)
This step configures the Transmit STS-3c POH Processor block to use the “TxPOH_n” input port as the
source for the Z4 byte, within each “outbound” STS-3c SPE. In this mode, the Transmit STS-3c POH
Processor block will accept the value, corresponding to the Z4 byte (via the “TxPOH_n” input port) and it will
write this data into the Z4 byte position, within the “outbound” STS-3c SPE.
STEP 2 – Begin providing the values of the “outbound” Z4 byte to the “TxPOH_n” input port.
The procedure for applying the Z4 byte to the “TxPOH_n” input port is presented below.
Using the “TxPOH” Input Port to insert the Z4 byte value into the outbound STS-3c SPE data-stream
If the user intends to externally insert the Z4 byte into the outbound STS-3c SPE, via the “TxPOH_n” input
port, then they must design some external circuitry (which can be realized in an ASIC, FPGA or CPLD
solution) to do to the following.
• Continuously sample the “TxPOHEnable_n” and the “TxPOHFrame_n” output pins upon the rising edge of
the “TxPOHClk_n” output clock signal.
A simple illustration of this “external circuit” being interfaced to the “TxPOH Input Port” is presented below in
Figure 43.
Figure 43: A Simple Illustration of the “External Circuit” being interfaced to the “TxPOH Input Port”
B
R/O
IT
0
7
B
R/O
IT
0
6
Unused
XRT95L34 Device
B
R/O
IT
0
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
5
TxPOHEnable_n
TxPOHFrame_n
TxPOHClk_n
TxPOHIns_n
TxPOH_n
B
R/O
IT
0
4
248
Z5 Insertion
B
Type
R/W
IT
0
3
TxPOHData_OUT
TxPOHFrame_IN
TxPOHEnable_IN
TxPOH_INSERT
TxPOHClk_IN
External Circuit
Z4 Insertion
B
Type
R/W
IT
1
2
Z3 Insertion
B
Type
R/W
IT
0
1
xr
H4 Insertion
Type
B
R/W
IT
0
0