FEDL7041-05
ML7041
CR2 (PCM CODEC operating mode setting and transmit/receive gain adjustment)
CR2
Initial Value
B7
B6
B5
B4
B3
B2
B1
B0
TX
ON/OFF
TX GAIN2 TX GAIN1 TX GAIN0
RX
ON/OFF
RX GAIN2 RX GAIN1
RX GAIN0
0
0
1
1
0
0
1
1
B7.................. Transmit side PCM signal ON/OFF
0: ON 1: OFF
B6, B5, B4 ..... Transmit side signal gain adjustment (refer to Table 2)
B3.................. Receive side PCM signal ON/OFF
0: ON 1: OFF
B2, B1, B0 ..... Receive side signal gain adjustment (refer to Table 2)
B6
B5
B4
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Table 2 Transmit/Receive Gain Settings
Transmit Gain
B2
B1
B0
–6 dB
0
0
0
–4 dB
0
0
1
–2 dB
0
1
0
0 dB
0
1
1
+2 dB
1
0
0
+4 dB
1
0
1
+6 dB
1
1
0
+8 dB
1
1
1
Receive Gain
–12 dB
–9 dB
–6 dB
–3 dB
0 dB
+3 dB
+6 dB
+9 dB
The above gain settings table shows the transmit/receive voice signal gain settings and the transmit side
gain settings for DTMF tones and other tones. The DTMF and other tone transmit signals are enabled
by CR4-B6, and the gain setting is referenced to the levels shown below.
DTMF tones (low group): .............................. –16 dBm0
DTMF tones (high group) and other tones:... –14 dBm0
For example, if the transmit gain set value is set to +8 dB (B6, B5, B4) = (1,1,1), then the following tones
are output at the PCMOUT pin.
DTMF tones (low group): .............................. –8 dBm0
DTMF tones (high group) and other tones:... –6 dBm0
Gains of the side tone (path to receive side from transmit side) and the receive side tone can be set by
register CR3.
21/28