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XRT94L33
xr
Rev.1.2.0.
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
238
2.2.7.3.6
SUPPORT/HANDLING OF THE F2 BYTE
The Transmit STS-3c POH Processor block permits the user to control the value of the F2 byte by either of
the following options.
Setting and controlling the “outbound” F2 Byte via Software
Setting and controlling the “outbound” F2 Byte via the “TxPOH Input Port”
The details and instructions for using either or these features are presented below.
2.2.7.3.6.1
Setting and Controlling the Outbound F2 Byte via Software
The Transmit STS-3c POH Processor block permits the user to specify the contents of the F2 byte, within the
“outbound” STS-3c SPE via software command.
The user can configure the Transmit STS-3c POH Processor block to accomplish this by performing the
following steps.
STEP 1 – Write the value “0” into Bit 7 (F2 Insertion Type) within the “Transmit STS-3c Path – SONET
Control Register – Byte 0”, as depicted below.
Transmit STS-3c Path – SONET Control Register – Byte 0 (Address = 0x1983)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
F2 Insertion
Type
REI-P Insertion Type[1:0]
RDI-P Insertion Type[1:0]
C2 Byte
Insertion
Type
Unused
Transmit
AIS-P
Enable
R/W
R/O
R/W
0
This step configures the Transmit STS-3c POH Processor block to read out the contents of the “Transmit
STS-3c Path – Transmit F2 Byte Value” register; and load this value into the F2 byte position within each
“outbound” STS-3c SPE.
STEP 2 – Write the desired byte value (for the outbound F2 byte) into the “Transmit STS-3c Path –
Transmit F2 Byte Value” register.
The bit-format of this register is presented below.
Transmit STS-3c Path – Transmit F2 Byte Value Register (Address = 0x19A3)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Transmit_F2_Byte_Value[7:0]
R/W
0
2.2.7.3.6.2
Setting and Controlling the Outbound F2 Byte via the “TxPOH_n Input Port”
The Transmit STS-3c POH Processor block permits the user to specify the contents of the F2 byte, within the
“outbound” STS-3c SPE, via data applied to the “TxPOH_n” input pin.
The user can configure the Transmit STS-3c POH Processor block to accomplish this by performing the
following steps.
STEP 1 – Write the value “1” into Bit 7 (F2 Byte Insertion Type) within the “Transmit STS-3c Path –
SONET Control Register – Byte 0”, as depicted below.