msm7718-01 Oki Semiconductor, msm7718-01 Datasheet - Page 11

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

¡ Semiconductor
VOXO
Signal output for transmit VOX function.
The VOX function recognizes the presence or absence of the transmit voice signal by detecting the
level of the transmit signal to the line echo canceler . “1” and “0” levels set to this pin correspond
to the presence and the absence of voice, respectively. This result appears also at the register data
CR7-B7. The signal energy detect threshold is set by the control register data CR6-B6, B5.
The timiging diagram of the VOX function is shown in Fig 6.
The transmit signal to the line echo canceler refers to the signal input to the PCMLNI pin.
VOXI
Signal input for receive VOX function.
The “1” level at VOXI indicates the presence of a voice signal, the decoder block processes normal
receive signal, and the voice signal on the PCMACI pin goes through. The “0” level indicates the
absence of a voice signal and the background noise generated in this device is output to the line echo
canceler.
The background noise amplitude is set by the control register CR6.
Because this signal is ORed with the register data CR6-B3, set the control register data CR6-B3 to logic
“0”.
DEN
EXCK
DIN
DOUT
DEN
EXCK
DIN
DOUT
   
       








High Impedance
W
R
A4
A4
Figure 5 MCU Interface Input/Output Timing
A3
A3

A2
A2
A1
A1
(a) Data Write Timing
(b) Data Read Timing
A0
A0
High Impedance
B7
B7
B6
B6
B5
B5
B4
B4
B3
B3
B2
B2
B1
B1
B0
B0
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