MSM7731-02 OKI [OKI electronic componets], MSM7731-02 Datasheet - Page 11

• Manufacturer Part Number: MSM7731-02
• Description: Dual Echo Canceler & Noise Canceler with Dual Codec for Hands-Free
• Manufacturer: OKI [OKI electronic componets]

NCSEL1, NCSEL2
These are the noise attenuation selection pins. In the “through mode” the noise canceler is halted and data is
directly output. In the “normal mode” the noise canceler operates normally. Since the noise attenuation in the
normal mode is selected after the initial mode has been released, the change of the noise attenuation during normal
operation is invalid. If the noise attenuation is changed, reset must be activated by the RDN/RST pin or the
PDN/RST bit (CR0-B7). Changing to the through mode during normal operation and returning to the normal mode
are possible. The NCSEL1 pin is ORed with the CR1-B0 bit of the control register and the NCSEL2 pin is ORed
with the CR12-B2 bit of the control register. Refer to the section “RELATIONSHIP BETWEEN PINS AND
CONTROL REGISTERS”.
Note:
Since there is a trade-off between noise attenuation and sound quality after canceling the noise, select the noise
attenuation appropriate to the sound quality.
NCPAD1, NCPAD2
These are the noise canceler I/O gain adjusting pins. The gain adjustment is valid for tone control after canceling
the noise. The bigger the input level of the noise canceler is, the better the sound quality is. The NCPAD1 pin is
ORed with the CR4-B2 bit of the control register and the NCPAD2 pin is ORed with the CR5-B2 bit of the control
register. Refer to the section “RELATIONSHIP BETWEEN PINS AND CONTROL REGISTERS”.
DEN
DEN
DEN
DEN, EXCK, DIN, DOUT
This is the serial port for the microcontroller interface. 13 bytes of control registers are provided in this IC device.
There pins are used to write and read data from an external microcontroller. The DEN pin is an enable signal input
pin, the EXCK pin is a clock signal input pin for data shifting, the DIN pin is an address and data input pin, the
DOUT pin is a data output pin. If the mirrocontroller interface is not used, set the DEN pin to a logic “1” and the
EXCK and DIN pins to a logic “0”. In addition, use the MCUSEL pin to specify the “unused” setting of the
microcontroller interface. Figure 4 shows the input timing.
MCUSEL
This pin selects whether the microcontroller interface is used or unused. A logic “0” specifies that the
microcontroller interface is used and a logic “1” specifies that it is not used. If the microcontroller interface is not
used, this pin must be set to a logic “1”. This pin is ORed with the CR0-B1 bit of the control register. Refer to the
section “RELATIONSHIP BETWEEN PINS AND CONTROL REGISTERS”.
1 Semiconductor
NCSEL2
NCPAD2
0
1
1
0
0
0
1
1
NCSEL1
0
1
0
1
NCPAD1
0
1
0
1
Through Mode
Normal Mode
Normal Mode
Normal Mode
NC Mode
GPADNC (dB)
12
18
0
6
Attenuation (dB)
13.5
17
—
8
LPADNC (dB)
FEDL7731-02-04
–12
–18
–6
MSM7731-02
Quality
0
Better
Best
—
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