msm7718-01 Oki Semiconductor, msm7718-01 Datasheet - Page 30

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

¡ Semiconductor
B7 ... Turns ON or OFF the VOX function.
B6, 5 ... Setting of transmit side voice or silence detection level
Note: • The detection level is changeable by inserting the pad of –1 dB to –5 dB in addition to the
B4 ... Setting of hangover time (T
B3 ... VOX input signal (receiver side)
B2 ... Setting of a receiver side background noise level
B1, 0 ... Externally-set background noise level
(8) CR7 (Detection register : read-only)
B7 ... Detection of transmit side voice or noise
B6, 5 ... Transmit side silence level (indicator)
B4 ... External interrupt signal
(7)CR6 (VOX function control)
CR7
Initial value
CR6
Initial value
0: 160 ms 1: 320 ms
0: Transmits an internal background noise.
1: Transmits a voice reception signal.
Set the VOXI pin to “0” to use this data.
0: Automatic internal setting
1: Reserved
(0, 0) : No noise
(0, 1) : –55 dBm0
(1, 0) : –45 dBm0
(1, 1) : –35 dBm0
0: Silence 1: Voice
(0, 0) : –10 dB or less with respect to the detection level defined by CR6-B6, B5.
(0, 1) : –5 to –10 dB with respect to the detection level defined by CR6-B6, B5.
(1, 0) : 0 to –5 dB with respect to the detection level defined by CR6-B6, B5.
(1, 1) : 0 dB or more. Refer to the detection level defined by CR6-B6, B5.
Note : The above outputs are valid only when the VOX function is enabled by bit 7 of CR6.
Goes to a logic “0” when any change has been found in the tone detection results for call
progress tone, DTMF tone, and 2100 Hz tone.
Goes to a logic “1” when the CR7 control register is read out .
The inverted state of this bit (B4) is output to the INT pin.
(0, 0) : –20 dBm0
(0, 1) : –25 dBm0
(1, 0) : –30 dBm0
(1, 1) : –35 dBm0
• Write 16384 ¥ 10
above values.
Example: When –1 dB pad is inserted, 16384 ¥ 10
=18383.15=18383d (eliminate after the decimal point)=47CFh
ON/OFF
VOX
OUT
VOX
B7
B7
0
0
(–A/20)
Silence level
LVL1
B6
B6
ON
1
0
0
at address "175h". (A=pad)
VXOFF
Silence level
) (see Figure 6)
LVL0
ON
B5
B5
0
0
0
0: OFF, 1: ON
TIME
INT
OFF
B4
B4
0
0
(– (–1)/20)
VOX
DET
CPT
B3
B3
IN
0
0
LEVEL SEL
RX. NOISE
DTMF
DET
B2
B2
0
0
RX. NOISE
DET21L
BUSY/
LVL1
B1
B1
0
0
MSM7718-01
RX. NOISE
DET21A
PRM/
LVL0
30/38
B0
B0
0
0