bt8970 Mindspeed Technologies, bt8970 Datasheet - Page 67

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

Bt8970
Single-Chip HDSL Transceiver
0x50, 0x51—Noise Level Meter Register (nlm_low, nlm_high)
A 2-byte read-only register containing 16 MSBs of the 32-bit unsigned noise-level meter accumulator. This
meter sums the absolute value of the detector’s slicer-error signal over each Meter Timer countdown interval.
Automatically loaded at the end of each interval, the meter register must be read the low byte first, followed by
high byte, unseparated by any other meter access (addresses 0x40 to 0x5F).
0x5E, 0x5F—PLL Frequency Register (pll_frequency_low, pll_frequency_high)
A 2-byte read/write register comprising 16 MSBs of the 31-bit, 2’s-complement timing recovery loop
compensation filter accumulator. Treated much like a meter register, the frequency register must be read low
byte first, followed by high byte, unseparated by any other Meter access (addresses 0x40 to 0x5F). Writes must
occur in the same order, with the low byte written first, followed by the high byte. Write accesses may be
separated by any number of other read or write accesses.
0x70—LEC Read Tap Select Register (linear_ec_tap_select_read)
A 7-bit read/write register representing an unsigned binary address defined over a range of 0 to 119 decimal.
When written, it causes the selected 32-bit coefficient of the LEC to be subsequently loaded into the Access
Data Register [access_data_byte[3:0]; 0x7C–0x7F] within two symbol periods. Does not affect the value of the
coefficient. No other data access may occur between the time the Read Tap Select Register is written and the
time the Access Data Register is read or the data may be corrupted.
0x71—LEC Write Tap Select Register (linear_ec_tap_select_write)
A 7-bit read/write register representing an unsigned binary address defined over a range of 0 to 119 decimal.
When written, it causes all 32 bits of the Access Data Register [access_data_byte[3:0]; 0x7C–0x7F] to be
subsequently written to the selected LEC coefficient within two symbol periods. Does not affect the value of the
access data register.
100101B
D[23]
D[31]
D[22]
D[30]
7
7
7
–
7
–
D[22]
D[30]
D[21]
D[29]
D[6]
D[6]
6
6
6
6
Preliminary Information/Conexant Proprietary and Confidential
D[21]
D[29]
D[20]
D[28]
D[5]
D[5]
5
5
5
5
D[20]
D[28]
D[19]
D[27]
D[4]
D[4]
4
4
4
4
Conexant
D[19]
D[27]
D[18]
D[26]
D[3]
D[3]
3
3
3
3
D[18]
D[26]
D[17]
D[25]
D[2]
D[2]
2
2
2
2
D[17]
D[25]
D[16]
D[24]
D[1]
D[1]
1
1
1
1
4.0 Register
D[16]
D[24]
D[15]
D[23]
D[0]
D[0]
0
0
0
0
4-23