cx28380 Mindspeed Technologies, cx28380 Datasheet - Page 28

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

2.4
Bipolar or unipolar NRZ digital transmit data are input on TPOSI and TNEGI using the transmit clock TCLK. Data is
converted into AMI pulses, shaped according to required standards, and transmitted to the line.
illustrates the relationship between the AMI transmitted signal, the transmit clock, and the data inputs. This section
discusses each transmitter block, from the digital inputs to the line output.
Figure 2-6.
2.4.1
The digital transmitter inputs, TPOSI[n] and TNEGI[n], accept bipolar or unipolar NRZ formatted data for
transmission and are sampled by the falling edge of TCLK[n], where [n] is channel number 1 to 4. TCLK[n] is the
line rate transmit clock and is normally supplied externally from a line rate source, but can also be sourced
internally (only in Host Mode) from the CLAD. If sourced internally, TCLK[n] is configured as an output to provide
the line rate clock to external circuitry. TCLK[n] direction is configured globally for all channels by writing to register
bit TCLK_I/O [GCR; addr 01].
2.4.1.1
In bipolar mode, TPOSI/TNEGI inputs accept bipolar dual-rail transmit data where a high on TPOSI causes a
positive output pulse and a high on TNEGI causes a negative output pulse on XTIP/XRING. In this mode, the
TZCS encoder is not available. In Hardware Mode, bipolar operation is enabled globally for all channels by pulling
the UNIPOLAR pin high. In Host Mode, bipolar operation is enabled per channel by writing a 0 to register bit
UNIPOLAR [RLIU_CR; addr n1].
2.4.1.2
In unipolar mode, TPOSI is replaced with TDATI and accepts unipolar NRZ-formatted transmit data. TNEGI is not
used in this mode. A high on TDATI causes an AMI pulse to be transmitted to the line. In this mode, the TZCS
encoder can be enabled to provide B8ZS or HDB3 zero code suppression. In Hardware Mode, unipolar operation is
29380-DSH-001-B
8380_010
(Unipolar)
(Bipolar)
(Bipolar)
XRING
TPOSI
TNEGI
TDATI
TCLK
XTIP,
Transmitter Signals
Transmitter
Transmit Digital Interface
Bipolar Mode
Unipolar Mode
1
Preliminary Information / Mindspeed Proprietary and Confidential
1
Throughput
Delay
0
Mindspeed Technologies
1
1
0
0
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1
Circuit Description
Figure 2-6
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