RS8973 Mindspeed Technologies, RS8973 Datasheet - Page 60

• Manufacturer Part Number: RS8973
• Description: Single-chip Sdsl/hdsl Transceiver
• Manufacturer: Mindspeed Technologies

3.0 Registers
3.3 Register Description
isolated_pulse[1,0]
transmitter_off
htur_lfsr
data_source[2:0]
3-14
0x0B—Transmitter Modes Register (transmitter_modes)
data_source [2:0]
—
7
000
001
010
011
100
101
110
111
isolated_pulse[1] isolated_pulse[0]
Isolated Pulse Level Select—Read/write binary field that selects one of four output pulse
levels while in the isolated pulse or alternating symbol transmitter mode.
Transmitter Off—Read/write control bit that zeros the output of the transmitter when set;
allows normal transmitter operation (as defined by data_source[2:0]) when cleared.
Remote Unit (HTU-R/NT) Polynomial Select—Read/write control bit selects one of two
feedback polynomials for the transmit scrambler. When set, this bit selects the remote unit
transmit polynomial
polynomial
Data Source—Read/write binary field that selects the data source and mode of the transmitter
output. The transmitter must be enabled (transmitter_off = 0) for these modes to be active.
6
Isolated pulse. Level selected by isolated_pulse[1:0]. The meter timer must be enabled and in the
continuous mode. The pulse repetition interval is determined by the meter timer countdown interval.
Four-level scrambled detector loopback. Sign and magnitude bits from the receiver detector are
scrambled and looped back to the transmitter. Feedback polynomial determined by the htur_lfsr control
bit.
Four-level unscrambled data. Transmits the four-level (2B1Q) sign and magnitude bits from the channel
unit transmit interface without scrambling.
Four-level scrambled 1s. Transmits a scrambled, constant high-logic level as a four-level (2B1Q) signal.
Feedback polynomial determined by the htur_lfsr control bit.
Alternating symbol mode. Outputs symbols of alternating polarity. Level is selected by
isolated_pulse[1:0]. The meter timer must be enabled and in continuous mode. The half period of the
output signal is defined by the meter timer countdown interval.
Four-level scrambled data. Scrambles and transmits the four-level (2B1Q) sign and magnitude bits from
the channel unit transmit interface. Feedback polynomial determined by the htur_lfsr control bit.
Two-level unscrambled data. Constantly forces the magnitude bit from the channel unit transmit interface
to a logical 0 and transmits the resulting two-level signal (as determined by the sign bit) without
scrambling. Valid output levels limited to + 3, – 3.
Two-level scrambled 1s. Transmits a scrambled, constant high-logic level as a two-level signal. The
feedback polynomial is determined by the htur_lfsr control bit. The scrambler is run at the symbol rate
(half-bit rate) to produce the sign bit of the transmitted signal while the magnitude bit is sourced with a
constant logical 0. Valid output levels are limited to + 3, – 3.
isolated_pulse[1,0]
x
–
23
5
+
x
00
01
10
11
x
–
–
5
23
+
+
transmitter_off
1
Preliminary Information
x
.
–
18
4
Conexant
+
1
Output Pulse Level
; when cleared, it selects the local unit (HTU-C/LT)
Transmitter Mode
htur_lfsr
3
+ 3
+ 1
– 3
– 1
data_source[2]
Single-Chip SDSL/HDSL Transceiver
2
data_source[1]
1
data_source[0]
N8973DSD
RS8973
0