bt8970 Mindspeed Technologies, bt8970 Datasheet - Page 32

• Manufacturer Part Number: bt8970
• Description: Single-chip Hdsl Transceiver
• Manufacturer: Mindspeed Technologies

2.0 Functional Description
2.4 Channel Unit Interface
2.4 Channel Unit Interface
The quaternary signals of the channel unit interface have four modes which are programmable through bits 0
and 1 of the Channel Unit Interface Modes Register [cu_interface_modes; 0x06]. They are: serial sign-bit first,
serial magnitude-bit first, parallel master, and parallel slave.
the receive data are output through RDAT on the rising edge of BCLK. The sign and magnitude bits of the
transmit data are sampled on the falling edge of BCLK at the TDAT input. The sign bit is transferred first,
followed by the magnitude bit of a given symbol in sign-bit first mode, while the opposite occurs in
magnitude-bit first mode. The clock relationships for serial sign-bit first mode are illustrated in
Figure 2-6. Serial Sign-Bit First Mode
respectively, on the rising edge of QCLK. The quaternary transmit data is sampled on the falling edge of QCLK.
This clock and data relationship is illustrated in
Figure 2-7. Parallel Master Mode
2-14
In serial mode, a Bit-Rate Clock (BCLK) is output at twice the symbol rate. The sign and magnitude bits of
In parallel master mode, the sign and magnitude receive data is output through RQ[1] and RQ[0],
RQ[1]/TQ[1]
RQ[0]/TQ[0]
Bit-Rate Clock
BCLK
RDAT
TDAT
QCLK
QCLK
Preliminary Information/Conexant Proprietary and Confidential
Sign
Sign
0
0
Magnitude
Sign
Magnitude
Magnitude
0
0
0
0
Figure
Conexant
Sign
Sign
2-7.
1
1
Magnitude
Sign
Magnitude
Magnitude
1
1
1
1
Sign
Sign
2
2
Magnitude
Sign
Single-Chip HDSL Transceiver
2
2
100101_010
100101_011
Figure
100101B
Bt8970
2-6.