bt8970 Mindspeed Technologies, bt8970 Datasheet - Page 58

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

4.0 Register
0x23—Test Register (reserved10)
A 3-byte read/write register used for device testing by Rockwell. This register is automatically initialized to
0x000000 upon RST assertion and initial power application. This register must be initialized according to the
device driver provided by Rockwell.
0x24, 0x25—Timing Recovery PLL Phase Offset Register (pll_phase_offset_low,
pll_phase_offset_high)
A 2-byte read/write register interpreted as a 16-bit, 2’s-complement number. The value of this register is
subtracted from the output of the timing-recovery phase detector after the phase-detector meter, but before the
loop compensation filter.
0x26, 0x27—Receiver DC Offset Register (dc_offset_low, dc_offset_high)
A 2-byte read/write register interpreted as a 16-bit, 2’s-complement number. The value of this register is
subtracted from the receiver signal path at the output of the digital front end’s format conversion block, ahead of
the DC level and signal level meters.
0x28—Transmitter Calibration Register (tx_calibrate)
tx_calibrate[3:0]
4-14
7
–
Transmit Calibrate—4-bit, 2’s-complement, read-only field containing the nominal setting for
the transmitter gain. The value of the Transmit Calibration Register is set during
manufacturing testing by Rockwell and corresponds to the value required to operate the
Bt8970 at a nominal 13.5 dBm transmit power, assuming the recommended transformer
coupling/hybrid circuit is used. Users may override this calibration by writing their own value
into the Transmitter Gain Register [tx_gain; 0x29].
6
–
Preliminary Information/Conexant Proprietary and Confidential
tx_calibrate[3]
5
tx_calibrate[2]
4
Conexant
tx_calibrate[1]
3
tx_calibrate[0]
2
Single-Chip HDSL Transceiver
1
–
100101B
Bt8970
0
–