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XRT94L33
3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
Rev.1.2.0.
439
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 Control Register – Byte 0, Address = 0x0403
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
UTOPIA
Level
Multi-PHY
Mode
Back-to-Back
Polling Enable
Direct Status
Access
Receive UTOPIA Data Bus
Width[1:0]
Cell_Size_Sel[1:0]
R/W
X
0
X
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.
UTOPIA Level 1 and 2 Operation
UTOPIA Level 3 Operation
SELECTING THE UTOPIA DATA BUS WIDTH
The UTOPIA data bus width can be selected 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 Control Register – Byte 0, Address = 0x0403
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
UTOPIA
Level
Multi-PHY
Mode
Back-to-Back
Polling Enable
Direct Status
Access
Receive UTOPIA Data
Bus Width[1:0]
Cell_Size_Sel[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 output: RxUData[15:0] will be active.
The following table relates the value of Bits 2 and 3 (Receive UTOPIA Data Bus Width[1:0]) within the
Receive UTOPIA Control Register, to the corresponding width of the UTOPIA Data bus.
Table 20 The Relationship between the contents of “Receive UTOPIA Data Bus Width[1:0] within the
Receive UTOPIA Control Register and the operating width of the UTOPIA Data Bus
RECEIVE UTOPIA DATA BUS
WIDTH[1:0]
WIDTH OF UTOPIA DATA BUS
00
In-active:
01
8 bits
10
16 bits
11
Not valid (do not use)