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OctalLIU
TM
PEF 22508 E
Functional Description
Data Sheet
76
Rev. 1.0, 2005-06-02
3.9.6.2
Programming with TXP(16:1) Registers
By setting of register bit XPM2.XPDIS the pulse shape will be configured by the registers TXP(16:1) (TXP1). Every
of these registers define the amplitude value of one sampling point in the symbol. A symbol is formed by 16
sampling points.
The default setting after reset for the registers TXP(16:1) generates also the E1 pulse shape (0m), but with an
unreduced amplitude. (TXP(9:16) = 00
H; TXP(1:8) = 38H= 56D) No reset value for T1 mode exists. So after
switching into T1 mode, an explicit new programming like Table 26 is necessary.
The pulse shape configuration will be done also by the registers TXP(16:1) if a LBO attenuation is selected. The
pulse shape is then determined by both, the values of TXP(16:1) and the LBO filtering.
The given values in Table 26 and Table 27 are optimized for transformer ratio: 1 : 2.4; cable: AWG24 and
0
122 to 162
399 to 533
5F
3F
11
0
162 to 200
533 to 655
3F
CB
11
7.5
---
Are not taken into account: pulse shape generation is
handled internally.
15
---
22.5
---
Table 25
Recommended Pulse Shaper Programming for E1 with Registers XPM(2:0) (Compatible to
OctalLIU
TM )
R
SER
Z
0
Transmit Line
Interface Mode
XPM0
XPM1
XPM2
()
(
)
Hexadecimal
7.5
1)
1) The values in this row refers to an ideal application without any parasitics. Any other parasitic resistances have to be taken
into account when calculating the final value of the output serial resistors.
120
Non generic
9C
03
00
7.5
75
Non generic
8D
03
00
---
Reset values
7B
03
40
7.5
DCIM Mode
Non generic
EF
BD
07
Table 26
Recommended Pulse Shaper Programming for T1 with registers TXP(16:1)
LBO
Range
TXP values, decimal
[dB]
[m]
[ft]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
0
0 to 40
0 to 133
46
44
16
-17 -14 -14 -4
-4
0
40 to 81
133 to 266 48
50
48
46
44
16
-17 -14 -14 -4
-4
0
81 to 122
266 to 399 56
58
54
52
48
16
-25 -17 -14 -4
-4
0
122 to 162 399 to 533 63
63
58
56
52
51
16
-34 -32 -17 -4
-4
0
162 to 200 533 to 655 63
63
58
50
-60 -26 -20 -12 -8
-6
-4
7.5
--
46
44
16
-17 -14 -14 -4
-4
155
--
46
44
16
-17 -14 -14 -4
-4
22.5
--
46
44
16
-17 -14 -14 -4
-4
Table 24
Recommended Pulse Shaper Programming for T1/J1 with Registers XPM(2:0) (Compatible to
QuadLIU (cont’d))
LBO
Range
XPM0
XPM1
XPM2