Version: 1.18
PRELIMINARY/CONFIDENTIAL
TrueSpeech® Co-Processor
9.19
Tone Generation In Idle Playback & Record Modes
This command is used to generate tones in IDLE, PLAYBACK and RECORD modes only. To generate DTMF
tones during Standalone Speakerphone mode, refer to the Speakerphone commands in Section 9.21. When tone
generation is completed in IDLE mode, the Host should use the Idle command to return the CT8022 to the IDLE
state.
Generate Tone Command:
0110
000
MASTER GAIN
(8-5)
TONE INDEX
(4-0)
(15-12)
(11-9)
MASTER GAIN:
Modifies (reduces) the level of the tone to be generated with respect to the level
programmed into the tone table. The level value in this field is added to the level value
programmed into the tone table. The resulting value is used to select the output level
(refer to table in Section 9.19.5). For example, if the Tone Table contains level 5, and the
master gain is set to level 8, the tone is actually output with a level value of 5 + 8 = 13.
The result of the addition is limited <= 15, so if the tone level is 8, and the master gain is
9, the result, 8+ 9 = 17, is limited to 15 and the tone is output using level value 15. An
alternate view of this control is to note that the output level is reduced by MASTER
GAIN x 2dB, with a minimum output level of -24 dB.
TONE INDEX:
Selects the tone to be generated.
Status:
0110
0000 000
(11-5)
MASTER GAIN
(4)
TONE INDEX
(3-0)
(15-12)
In IDLE mode, with default output CODEC routing (= 00) tone is output via CODEC0 only (telephone line side).
To output tone to CODEC1, change the output CODEC routing in the CODEC configuration command.
In PLAYBACK or RECORD mode, tone is output to the default CODEC (normally CODEC1) unless over-ridden
by the CODEC configuration command
Tone generation is possible in two modes: synchronous or asynchronous. Tone generation can be directed to the
compressed audio stream using the loopback configuration.
9.19.1
Stop Tone Generation
To terminate tone generation in IDLE mode, use the IDLE command 0000H.
To terminate tone generation during playback/record mode use the following command:
Stop Tone:
Command: 6E0AH
Status:
6E0AH
Note that when generating tones during playback/record, it is recommended that tone generation be configured for
asynchronous mode. If tones are generated during playback, the tone output replaces the normal output audio data
generated by the playback data. Playback data is consumed at the normal rate even when tone generation is active.
CT8022A11AQC FW Revision 0118 DSP GROUP, INC., 3120 SCOTT BOULEVARD
SANTA CLARA, CA 95054 PH: 408 986 – 4300 FAX: 408 986 – 4490
123
All specifications are subject to change without prior notice.
ETC [ ETC ]
