RS8973 Mindspeed Technologies, RS8973 Datasheet - Page 69

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

RS8973
Single-Chip SDSL/HDSL Transceiver
enable_peak_
detector
output_mux_
control[1,0]
scr_out_to_dfe
two_level
N8973DSD
0x3A—Symbol Detector Modes Register (detector_modes)
enable_peak_
detector
7
output_mux_
control[1]
Enable Peak Detector—Read/write control bit that enables the peak detection function when
set; disables the function when cleared. When enabled, the peak detector output overrides the
slicer output if the peak detection criteria are met. If the criteria are not met, or if the function
is disabled, the slicer output is used and peak detector output is ignored.
Output Multiplexer Control—Read/write binary field that selects the source of the detector
output connected to the channel unit receive interface.
Scrambler Output to DFE—Read/write control bit that selects the source of the detector output
connected to the DFE and timing recovery module inputs and the transmitter’s detector
loopback input. When set, this bit selects the scrambler/descrambler function; when cleared, it
selects the slicer/peak detector output.
Two-Level Mode—Read/write control bit that selects two-level mode when set, four-level
mode when cleared. Affects the slicer and the scrambler/descrambler function. In two-level
mode, the slicer uses a single threshold set at zero to recover sign bits only; all magnitude
information is lost. Scrambler/descrambler updates are slowed to the symbol rate (half the
normal bit rate) to process only sign information as well; all magnitude output bits are sourced
with a constant logic zero value, producing two-level symbols constrained to +3 and –3 values.
[cursor_level_low, cursor_level_high; 0x36–0x37], as well as the zero threshold, to recover
both sign and magnitude information. The scrambler/descrambler is updated at the full bit rate
to process both sign and magnitude bits as well.
In four-level mode, the slicer uses two thresholds derived from the Cursor Level Register
6
output_mux_
output_mux_control[1,0]
control[0]
5
00
01
10
11
scr_out_to_dfe
Preliminary Information
4
Conexant
two_level
Detector Output to CU Receive Interface
Same as scr_out_to_dfe selection
Transmitter loopback output from CU
transmit interface
Scrambler/descrambler output
Reserved
3
lfsr_lock
2
htur_lfsr
3.3 Register Description
1
3.0 Registers
descr_on
0
3-23