zic2410 California Eastern Laboratories, zic2410 Datasheet - Page 47

• Manufacturer Part Number: zic2410
• Description: Single-chip Solution, Compliant With Zigbee
• Manufacturer: California Eastern Laboratories

quantization error (hence increasing signal to quantization noise ratio). These SNR
improvements can be traded for reduced bandwidth and equivalent SNR instead.
The a-law algorithm is a standard companding algorithm used in European digital
communications systems to optimize/modify the dynamic range of an analog signal for
digitizing.
The a-law algorithm provides a slightly larger dynamic range than the μ-law at the cost of worse
proportional distortion for small signals.
Adaptive DPCM (ADPCM) is a variant of DPCM (Differential (or Delta) pulse-code modulation)
that varies the size of the quantization step, to allow further reduction of the required bandwidth
for a given signal-to-noise ratio. DPCM encodes the PCM values as differences between the
current and the previous value. For audio this type of encoding reduces the number of bits
required per sample by about 25% compared to PCM.
In order to control voice codec, there are several registers. This section describes the major
commonly used registers. For more detailed information, please contact CEL.
ENCCTL (VOICE ENCODER CONTROL REGISTER, 0x2745)
DECCTL (VOICE DECODER CONTROL REGISTER, 0x274D)
Bit
7:6
3:2
3:2
5
4
1
0
7
6
5
4
1
0
Rev A
Name
MUT
MUT
ENA
ENA
SEL
LPB
SEL
B16
B16
INI
INI
Reserved
When the bit width of data received to voice encoder is 16-bit, set
this field to ‘1’. When it is 8-bit, set this field to ‘0’.
Mute Enable. When this field is set to ‘1’, the Mute function is
enabled. ENCMUT1 and ENCMUT0 values are input to the voice
encoder block.
Encoder Select. Selects voice encoder algorithm.
Encoder Initialize. When this field is set to ‘1’, the pointer in voice
encoder is initialized. This field cannot be read.
Encoder Enable. When this field is set to ‘1’, voice encoder acts.
Loopback Test. When this field is set to ‘1’, Loopback test mode
is selected. In this case, the output of voice encoder is connected
to the input of voice decoder.
Reserved
The bit width of data which is output from voice decoder is 16-bit,
set this field to ‘1’. When this field is set to ‘0’, the bit width of data
which is output from voice decoder is 8-bit.
Mute Enable. When this field is set to ‘1’, Mute function is enabled.
DECMUT1 and DECMUT0 values are transferred from voice
decoder.
Decoder Select. Select voice decoder.
When this field is set to ‘1’, the pointer in voice decoder is
initialized. This field cannot be read.
Decoder Enable.
0: No Encoding
1: µ-law
2: a-law
3: ADPCM
0: No Decoding
1: µ-law
2: a-law
3: ADPCM
Document No. 0005-05-07-00-000
Table 27 – VODEC Registers
ZIC2410 Datasheet
Descriptions
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Page 47 of 119
W
W
Reset
Value
0
0
0
0
0
0
0
0
0
0
0
0
0