msm7617 Oki Semiconductor, msm7617 Datasheet - Page 7

• Manufacturer Part Number: msm7617
• Description: 2-channel Echo Canceler
• Manufacturer: Oki Semiconductor

¡ Semiconductor
PIN DESCRIPTIONS (Continued)
Pin
17
18
19
Symbol
SOUT1
ATT1
HD1
Type
O
I
I
Howling detection control pin for channel 1.
This pin controls detection and canceling of howling generated by the
acoustics of handsfree telephones.
ATT control pin for channel 1.
This pin controls the ATT function for preventing howling with the
attenuators (ATT) provided on RIN and SOUT. When input is only on RIN,
the SOUT attenuator is activated. When there is no input on RIN or there is
input on both SIN and RIN, the RIN input attenuator is activated. Either the
ATT for the RIN output or the ATT for the SOUT is always activated in all
cases, and the attenuation of ATT is 6 dB.
Because the attenuator is inserted opposite the speaker, it is effective for
further reducing echo.
PCM data output pin. Output signal changes depending on the setting of
the IOM pins (refer to the block diagram).
Data is always output on the rising edge of SCK. This pin is put in high
impedance state while there is no data or during reset.
In 2-channel parallel I/O mode, this pin becomes SOUT for channel 1 and
outputs the PCM signal synchronous with SYNC1. In 2-channel serial I/O
mode, this pin outputs the SOUT signal as a multiplexed PCM signal of
SOUT signal for channel 1 and channel 2 synchronous with SYNC1.
In 1-channel cross-connected mode, this pin becomes high impedance.
"L": Howling detector on
"H": Howling detector off
"H": Attenuator off
"L": Attenuator on
Description
MSM7617
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