IDT82V2044E データシートの表示（PDF） - Integrated Device Technology
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IDT82V2044E Datasheet PDF : 73 Pages
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QUAD CHANNEL T1/E1/J1 SHORT HAUL LINE INTERFACE UNIT
INDUSTRIAL
TEMPERATURE RANGES
TTIPn
IDT82V2044E
TRINGn
Cable
RLOAD VOUT
Note: RLOAD = 100 Ω ± 5%
Figure-6 T1 Pulse Template Test Circuit
For J1 applications, the PULS[3:0] (TCF1, 03H...) should be set to
‘0111’. Table-10 lists these values.
3.2.3.2 User-Programmable Arbitrary Waveform
When the PULS[3:0] bits are set to ‘11xx’, user-programmable arbitrary
waveform generator mode can be used in the corresponding channel. This
allows the transmitter performance to be tuned for a wide variety of line con-
dition or special application.
Each pulse shape can extend up to 4 UIs (Unit Interval), addressed by
UI[1:0] bits (TCF3, 05H...) and each UI is divided into 16 sub-phases,
addressed by the SAMP[3:0] bits (TCF3, 05H...). The pulse amplitude of
each phase is represented by a binary byte, within the range from +63 to -
63, stored in WDAT[6:0] bits (TCF4, 06H...) in signed magnitude form. The
most positive number +63 (D) represents the maximum positive amplitude
of the transmit pulse while the most negative number -63 (D) represents the
maximum negative amplitude of the transmit pulse. Therefore, up to 64
bytes are used. For each channel, a 64 bytes RAM is available.
There are eight standard templates which are stored in a local ROM.
User can select one of them as reference and make some changes to get
the desired waveform.
User can change the wave shape and the amplitude to get the desired
pulse shape. In order to do this, firstly, users can choose a set of waveform
value from the following eight tables, which is the most similar to the desired
pulse shape. Table-2, Table-3, Table-4, Table-5, Table-6, Table-7, Table-8
and Table-9 list the sample data and scaling data of each of the eight tem-
plates. Then modify the corresponding sample data to get the desired trans-
mit pulse shape.
Secondly, through the value of SCAL[5:0] bits increased or decreased
by 1, the pulse amplitude can be scaled up or down at the percentage ratio
against the standard pulse amplitude if needed. For different pulse shapes,
the value of SCAL[5:0] bits and the scaling percentage ratio are different.
The following eight tables list these values.
Do the followings step by step, the desired waveform can be pro-
grammed, based on the selected waveform template:
(1).Select the UI by UI[1:0] bits (TCF3, 05H...)
(2).Specify the sample address in the selected UI by SAMP [3:0] bits
(TCF3, 05H...)
(3).Write sample data to WDAT[6:0] bits (TCF4, 06H...). It contains the
data to be stored in the RAM, addressed by the selected UI and the
corresponding sample address.
(4).Set the RW bit (TCF3, 05H...) to ‘0’ to implement writing data to RAM,
or to ‘1’ to implement read data from RAM
(5).Implement the Read from RAM/Write to RAM by setting the DONE
bit (TCF3, 05H...)
Repeat the above steps until all the sample data are written to or read
from the internal RAM.
(6).Write the scaling data to SCAL[5:0] bits (TCF2, 04H...) to scale the
amplitude of the waveform based on the selected standard pulse
amplitude
When more than one UI is used to compose the pulse template, the over-
lap of two consecutive pulses could make the pulse amplitude overflow
(exceed the maximum limitation) if the pulse amplitude is not set properly.
This overflow is captured by DAC_OV_IS bit (INTS1, 17H...), and, if
enabled by the DAC_OV_IM bit (INTM1, 12H...), an interrupt will be gen-
erated.
The following tables give all the sample data based on the preset pulse
templates in detail for reference. For preset pulse templates, scaling up/
down against the pulse amplitude is not supported.
1.Table-2 Transmit Waveform Value For E1 75 Ω
2.Table-3 Transmit Waveform Value For E1 120 Ω
3.Table-4 Transmit Waveform Value For T1 0~133 ft
4.Table-5 Transmit Waveform Value For T1 133~266 ft
5.Table-6 Transmit Waveform Value For T1 266~399 ft
6.Table-7 Transmit Waveform Value For T1 399~533 ft
7.Table-8 Transmit Waveform Value For T1 533~655 ft
8.Table-9 Transmit Waveform Value For J1 0~655 ft
Table-2 Transmit Waveform Value For E1 75 Ω
Sample
UI 1
UI 2
UI 3
UI 4
1
0000000 0000000
0000000
0000000
2
0000000 0000000
0000000
0000000
3
0000000 0000000
0000000
0000000
4
0001100 0000000
0000000
0000000
5
0110000 0000000
0000000
0000000
6
0110000 0000000
0000000
0000000
7
0110000 0000000
0000000
0000000
8
0110000 0000000
0000000
0000000
9
0110000 0000000
0000000
0000000
10
0110000 0000000
0000000
0000000
11
0110000 0000000
0000000
0000000
12
0110000 0000000
0000000
0000000
13
0000000 0000000
0000000
0000000
14
0000000 0000000
0000000
0000000
15
0000000 0000000
0000000
0000000
16
0000000 0000000
0000000
0000000
SCAL[5:0] = 100001 (default), One step change of this value of SCAL[5:0]
results in 3% scaling up/down against the pulse amplitude.
15
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