msm7718-01 Oki Semiconductor, msm7718-01 Datasheet - Page 22

• Manufacturer Part Number: msm7718-01
• Description: Echo Canceler With Adpcm Codec
• Manufacturer: Oki Semiconductor

¡ Semiconductor
(1)CR0 (Basic operating mode settings)
* :
B7 ... Not used
B6 ... Power-down (entire system)
B5 ... Power-down reset (entire system)
B4 ... Not used
B3, 2, 1, 0 ...... Selection of an operating mode
CR0
Initial value *
Indicates the value to be set when a resetting is made through the PDN/RST pin. (Also
when reset by bit 5 (B5, PDN/RST), the other bits of CR0 are reset to initial values.)
ORed with the inverted external power-down signals
Set the PDWN pin to “1” when this data is used. The control registers and their internal
variables are not reset.
ORed with the inverted external power-down reset signals
Set the PDN/RST pin to “1” when this data is used .
(0, 0, 0, 0) : Initial mode
This mode enables a change (see Figure 15-1, 2) in memory that contains internal default values such
as tone generation frequencies.
In this mode, the PCM output pin acts to output idle patterns and the PCM input pin acts to
input idle patterns. When a reset or power-down occurs or when power down is released,
the device enters the initial mode about 200 ms after that.
(0, 0, 0, 1) : Reserved
(0, 0, 1, 0) : Normal speech mode (see Figure 7-1)
This mode enables call services between a slave telephone and a line (including tone
generation) and detection of a DTMF tone and a call progress tone.
The internal process enables the tone detector. The ADPCM encoder/decoder, the tone
generator, and the line echo canceler become operative and can be controlled by the contents
of the control registers.
(0, 0, 1, 1) to (0, 1, 0, 0) : Reserved
(0, 1, 0, 1) : Line echo canceler expansion mode (see Figure 7-2)
This mode can expand the delay time of the line echo canceler up to 54 ms.
Concerning the internal processing, the ADPCM encoder/decoder, the line echo canceler, and
the tone generator become operative and can be controlled by the contents of the control
registers.
In addition, 2100 Hz tone of PCMLNI and PCMACI (bidirectional) can be detected.
(0, 1, 1, 0) to (1, 1, 1, 1) : Reserved
B7
—
0
PDWN
B6
0
PDN/RST
B5
0
0: Power-on 1: Power-down
0: Power-on 1: Power-down reset
B4
—
0
MODE3
OPE
B3
0
MODE2
OPE
B2
0
MODE1
OPE
B1
0
MSM7718-01
MODE0
OPE
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B0
0