NAU8812EVB Nuvoton Technology Corporation of America, NAU8812EVB Datasheet - Page 25

• Manufacturer Part Number: NAU8812EVB
• Description: BOARD EVAL FOR NAU8812
• Manufacturer: Nuvoton Technology Corporation of America
• Series: emPowerAudio™r

Specifications of NAU8812EVB

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The high pass filter (HPF) has two different modes that it can operate in either Audio or Application mode HPFAM[7]
address (0x0E). In Audio Mode (HPFAM=0) the filter is first order, with a cut-off frequency of 3.7kHz. In Application
mode (HPFAM=1) the filter is second order, with a cut-off frequency selectable via the HPF[2:0] register bits. Cut-off
frequency of the HPF depends on sample frequency selected by SMPLR[3:1] address (0x07). The HPF is enabled
by setting HPFEN[8] address (0x0E) to HIGH. Table below shows the cut-off frequencies with different sampling
rate.
The NAU8812 has a programmable notch filter where it passes all frequencies except those in a stop band centered
on a given center frequency. The filter gives lower distortion and flattens response. The notch filter is enabled by
setting NFCEN[7] address (0x1B) to HIGH.
complement values to NFCA0[6:0] address (0x1C), NFCA0[13:7] address (0x1B) and NFCA1[6:0] address (0x1E),
NFCA1[13:7] address (0x1D) registers. The coefficients are updated in the circuit when the NFCU[8] bit is set HIGH
in a write to any of the registers NF1-NF4 address (0x1B, 0x1C, 0x1D, 0x1E).
emPowerAudio
Datasheet Revision 2.0
0x1C
0x1D
0x1B
0x1E
Addr
12.3.1. Programmable High Pass Filter (HPF)
12.3.2. Programmable Notch Filter (NF)
HPF[2:0]
NFCU
NFCU
NFCU
NFCU
000
001
010
011
100
101
110
111
Bit 8
™
NFCEN
102
131
163
204
261
327
408
Bit 7
82
8
0
0
0
SMPLR=101/100
Table 10: High Pass Filter Cut-off Frequencies (HPFAM=1)
Table 11: Registers associated with Notch Filter Function
11.025
113
141
180
225
281
360
450
563
Bit 6
122
153
156
245
306
392
490
612
Bit5
12
Page 25 of 109
The variable center frequency is programmed by setting two‟s
Bit 4
102
131
163
204
261
327
408
16
82
SMPLR=011/010
fs (kHz)
NFCA0[13:7]
NFCA1[13:7]
NFCA0[6:0]
NFCA1[6:0]
22.05
Bit 3
113
141
180
225
281
360
450
563
122
153
156
245
306
392
490
612
24
Bit 2
102
131
163
204
261
327
408
32
82
SMPLR=001/000
Bit 1
44.1
113
141
180
225
281
360
450
NAU8812
563
January 2011
Bit 0
122
153
156
245
306
392
490
612
48
Default
0x000
0x000
0x000
0x000