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XRT94L33
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
Rev.1.2.0.
445
CONFIGURATION OPTIONS WITH THE RECEIVE UTOPIA INTERFACE BLOCK
Selecting the UTOPIA Level
The XRT94L33 permits the user to configure the Receive UTOPIA Interface block in either of the following
“UTOPIA Levels”.
UTOPIA Level 3
UTOPIA Level 1 or 2
The user can configure the Receive UTOPIA Interface block (within the XRT94L33) to operate in the
appropriate UTOPIA Level, by writing the appropriate value into Bit 7 (UTOPIA Level) within the “Receive
UTOPIA Control Register”, as depicted below.
Receive UTOPIA/POS-PHY Control Register – Byte 0 (Address = 0x0503)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
UTOPIA
Level 3
Disable
Multi-PHY
Polling
Enable
Back to
Back Polling
Enable
Direct
Status
Indication
Enable
Receive UTOPIA/POS-PHY
Data Bus Width
Cell Size[1:0]
R/W
X
1
0
1
Setting this bit-field to “0” configures the Receive UTOPIA Interface block to support “UTOPIA Level 3”
signaling. Conversely, setting this bit-field to “1” configures the Receive UTOPIA Interface block to support
the “UTOPIA Levels 1 and 2” form of signaling.
A description of the operation of the Receive UTOPIA
Interface block, for UTOPIA Level 1, 2 and 3 operation is presented below.
2.3.5.1.2
UTOPIA Level 1 and 2 Operation of the Receive UTOPIA Interface Block
This section presents an in-depth write up of the UTOPIA Level 1 and 2 protocols.
When the Receive UTOPIA Interface block has been configured to operate in the “UTOPIA Level 2” Mode,
then it will either be configured to operate in the “Single-PHY” or “Multi-PHY” mode, as described below.
2.3.5.1.2.1
Selecting the UTOPIA Data Bus Width
The user can configure the width of the Receive UTOPIA Data Bus to be either 8 or 16 bits by writing the
appropriate data into Bits 3 and 2 (Receive UTOPIA Data Bus Width[1:0]) within the “Receive UTOPIA
Control” Register, as depicted below.
Receive UTOPIA/POS-PHY Control Register – Byte 0 (Address = 0x0503)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
UTOPIA
Level 3
Disable
Multi-PHY
Polling
Enable
Back to
Back Polling
Enable
Direct
Status
Indication
Enable
Receive UTOPIA/POS-PHY
Data Bus Width
Cell Size[1:0]
R/W
1
0
X
1
If the user chooses a UTOPIA Data Bus width of 8 bits, then only the Receive UTOPIA Data outputs:
RxUData[15:8] will be active.
(The output pins: RxUData[7:0] will not be active).
If the user chooses a
UTOPIA Data Bus width of 16 bits, then all of the Receive UTOPIA Data outputs: RxUData[15:0] will be