cx28380 Mindspeed Technologies, cx28380 Datasheet - Page 55

• Manufacturer Part Number: cx28380
• Description: Cn8380 Quad T1/e1 Line Interface
• Manufacturer: Mindspeed Technologies

11, 21, 31, 41—Receiver Configuration (RLIU_CR)
UNIPOLAR
ZCS
CLK_POL
RAWMD
EQ_DIS
ATTN
29380-DSH-001-B
UNIPOLAR
7
Unipolar Mode
signals.
encoded received data is decoded and output on RDATO in unipolar, NRZ format; and BPV
indicates that the currently received bit is a bipolar violation. TPOSI is replaced with TDATI
and accepts unipolar, NRZ formatted transmit data. TNEGI is not used in this mode. In
unipolar mode, ZCS can replace AMI encoding. See the ZCS bit description below.
where a high level on RPOSO indicates receipt of a positive AMI pulse, and a high level on
RNEGO indicates receipt of a negative AMI pulse on RTIP/RING inputs. TPOSI/TNEGI inputs
accept bipolar dual-rail transmit data, where a high on TPOSI causes a positive output pulse
on XTIP/XRING, and a high on TNEGI causes a negative output pulse.
Zero Code Suppression Enable
decoding on digital transmit and receive signals and is only applicable if unipolar mode is
selected. In T1 mode (T1/E1 = 1) [addr n0], B8ZS encoding/decoding is selected. In E1 mode
(T1/E1 = 0), HDB3 encoding/decoding is selected.
recoverable code. In the receive direction, the ZCS decoder replaces received codes with
eight 0s in T1 mode, or four 0s in E1 mode. The B8ZS code is 000VB0VB and the HDB3 code
is X00V; where B is a normal AMI pulse, V is a bipolar violation, and X is a “don't-care.” These
are standard T1 and E1 line code options.
Clock Polarity
output on the rising edge of RCKO. If CLK_POL is set to 1, RPOSO/RNEGO is output on the
falling edge of RCKO.
Raw Receive Mode
RCKO is replaced by the logical OR of RPOSO/RNEGO. A high on RPOSO indicates a positive
pulse, and a high on RNEGO indicates a negative pulse on RTIP/RRING line inputs.
Equalizer Disable
Bridge Attenuation
of bridge resistors in series with the normal receive termination resistance. Also, in this mode a
lower threshold for RALOS is selected to compensate for the 20 dB attenuation.
In unipolar mode, RPOSO/RNEGO signals are replaced by RDATO/BPV signals. AMI
In bipolar mode, RPOSO/RNEGO signals output received data in bipolar dual-rail format,
0 = Digital transmit/receive signals are bipolar, dual-rail
1 = Digital transmit/receive signals are unipolar, NRZ
In the transmit direction, the ZCS encoder replaces sequences of eight or four 0s with a
0 = ZCS encode/decode disabled
1 = ZCS encode/decode enabled
0 = Data out on rising RCKO
1 = Data out on falling RCKO
0 = Normal receiver output
1 = Slicer data output enabled
0 = Equalizer enabled
1 = Equalizer disabled
0 = Normal receiver input levels
1 = 20 dB compensation enabled
ZCS
6
Preliminary Information / Mindspeed Proprietary and Confidential
—
—
CLK_POL
Selects the digital receive data clocking edge. Normally, RPOSO/RNEGO is
Selects between unipolar and bipolar modes for digital transmit and receive
—
5
—
Disables the receiver equalizer. (Test mode only)
—
Mindspeed Technologies
Compensates for 20 dB resistive signal attenuation caused by placement
RPOSO/RNEGO data outputs are replaced by the data slicer output, and
RAWMD
—
4
Enables HDB3 or B8ZS zero code suppression encoding/
EQ_DIS
3
®
ATTN
2
—
1
Registers
SENS
0
R/W
47