xrt94l33 Exar Corporation, xrt94l33 Datasheet - Page 252

• 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.
• To force a “Positive-Stuff” pointer-adjustment event
• To force a “Negative-Stuff” pointer-adjustment event
• To force a Single NDF Event
• To force a Continuous NDF Event
• To read out and determine the current “pointer-value” within the outbound STS-3c data-stream.
The procedure for implementing each of these “pointer-related” events is presented below.
Forcing the Pointer to Shift to an Arbitrary Value
The Transmit STS-3c POH Processor block permits the user to assign the arbitrary value to the pointer bytes,
within the outbound STS-3c SPE data-stream. The user can invoke this feature by executing the following
steps.
STEP 1 – Write the appropriate “NDF”, “SS” and H1, H2 Pointer values into the “Transmit STS-3c Path
– Transmit Arbitrary H1 Pointer” register, and the “Transmit STS-3c Path – Transmit Arbitrary H2
Pointer” register.
The bit-format for these two registers is presented below.
Transmit STS-3c Path – Transmit Arbitrary H1 Byte Pointer Register (Address = 0x19BF)
Transmit STS-3c Path – Transmit Arbitrary H2 Byte Pointer Register (Address = 0x19C3)
STEP 2 – Induce a “0 to 1 transition” in Bit 5 (Pointer Force) within the “Transmit STS-3c Path –
Transmit Path Control Register, as depicted below.
Transmit STS-3c Path – Transmit Path Control Register (Address = 0x19B7)
Once the user induces this “0 to 1 transition” in Bit 5, then the following events will occur, within the very next
“outbound” STS-3c frame.
• The NDF bits, within the H1 byte, will be set to the value written into Bits 4 through 7 (NDF Bits) within the
“Transmit STS-3c Path – Transmit Arbitrary H1 Byte Pointer Register.
B
B
B
R/W
R/W
R/O
IT
IT
IT
0
0
0
7
7
7
Unused
B
B
B
R/W
R/W
R/O
IT
IT
IT
0
0
0
6
6
6
NDF Bits
Pointer
Force
B
0 ->1
B
B
R/W
R/W
R/W
IT
IT
IT
0
0
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
5
5
5
Check Stuff
H2 Pointer Value[7:0]
B
B
B
R/W
R/W
R/W
IT
IT
IT
0
0
0
4
4
4
252
Negative
Insert
B
B
B
Stuff
R/W
R/W
W
IT
IT
IT
0
0
0
3
3
3
SS Bits
Positive
Insert
B
B
B
Stuff
R/W
R/W
W
IT
IT
IT
0
0
0
2
2
2
NDF Events
Continuous
Insert
B
B
B
R/W
R/W
R/W
IT
H1 Pointer Value
IT
IT
0
0
0
1
1
1
xr
Single NDF
Event
Insert
B
B
B
R/W
R/W
R/W
IT
IT
IT
0
0
0
0
0
0