Silicon Laboratories SI2493/57/34/15/04 - Manual (Page 186)

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186 Rev. 1.3
The SMUTE bit (U199 [1]) mutes the speaker output audio path. The bit should be cleared for normal
speakerphone operation. For recording during hands-free TAM, the bit should be set to mute the speaker output.
The MMUTE bit (U199 [3]) mutes the microphone input audio path. The bit should be cleared for the normal
speakerphone operation. For message review during hands-free TAM, the bit should be set to mute the
microphone.
Bit SPCAL (U199 [2]) in U199 must be set for speakerphone’s calibration and cleared for normal speakerphone
operation.
Bit fields SPKREF and MICREF in U19E contain the speakerphone’s speaker and microphone levels during
speakerphone calibration.
Table 115. U199 and U19E Register Bit Maps
Reg Name Bits
15-9
Bit8 Bit7 Bit6 Bits
4-5
Bit 3 Bit 2 Bit 1 Bit 0
U199 VPCTRL SSP_LOCTALK SSP_PTT SSP_FLAG MMUTE SPCAL SMUTE
U19E AECREF SPKREF MICREF
Table 116. U199 Bit Definitions
Bit Name Function
8 SSP_LOCTALK 1 = Local talker enabled
0 = Remote talker enabled
Toggled by <0x27>
7 SSP_PTT 1 = Manually switch between near/far talker (push-to-talk mode)
0 = Automatically switch based on signal levels
Toggled by <0x26>
6 SSP_FLAG 1 = Enable SSP mode
0 = Disable SSP mode
Toggled by <0x25>
3 MMUTE 1 = Mute speaker of speakerphone or handset
0 = Unmute speaker
2 SPCAL 1 = AEC speaker / microphone calibration
0 = Normal mode
1 SMUTE 1 = Mute local talker
0 = Unmute local talker