Silicon Laboratories SI2493/57/34/15/04 - Manual (Page 200)

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200 Rev. 1.3
7.5.8. Speakerphone Transition
In the Handset mode, the SP Button On Event will trigger the transition from Handset to Speakerphone mode. See
"7.7. Speakerphone" on page 212 for details on Speakerphone mode. The voice driver should track the handset
hook switch state, such that if the user exits Speakerphone mode, the system will switch back to Handset
configuration without losing the active call.
Table 125. Handset to Speakerphone Transition
Host to Modem
Commands / Data
Modem to Host Result
Codes/Data
Local Modem Actions
AT:U199|A OK Mute the microphone and speaker paths to the codec.
AT:U72,0108 OK
Configure Si3000 Register 1:
Disable speaker driver
Enable line output driver
Disable telephone instrument driver
Disable MBIAS output
AT:U72,05D7 OK
Configure Si3000 Register 5:
20 dB Line In gain
Enable Line In
20 dB MIC input gain
Mute MIC input
Mute telephone instrument input
Enable IIR filter
AT:U72,065E OK
Configure Si3000 Register 6:
0 dB RX PGA gain
Enable Line Out
Disable telephone instrument output
AT:U72,075E OK
Configure Si3000 Register 7:
0 dB RX PGA gain
Enable SPKRL
Mute SPKRR
AT:U72,0900 OK
Configure Si3000 Register 9:
0 dB Line Out attenuation
0 dB Speaker output attenuation
AT+VSP=1 OK
Enable speakerphone voice path. See Figure 29 on
page 188 for details.
AT:U199&FFF5 OK Enable the microphone and speaker paths to the codec.