NXP Semiconductors SLN-LOCAL2-IOT, Руководство пользователя

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Figure 62. ASR session control - follow-up mode
7.1.4.2 Timeout
After the device is triggered by a wake word, it waits for the user’s voice command for a certain amount of time. Users can configure
the response waiting time using a shell command in a serial terminal.
Figure 63 shows the command usage.
Figure 63. ASR session control - timeout
7.1.4.3 Push-to-Talk (PTT) mode
In some applications, you may want to bypass the wake word detection stage. The SLN-LOCAL2-IOT kit offers the PTT feature.
If it is enabled, you can directly say voice commands after pressing the SW1 button on the device.
Figure 64 shows the
command usage.
Figure 64. ASR session control - PTT mode
7.2 Acoustic modification
7.2.1 Changing microphone configuration
Open the local _demo variant of the project in the developer’s environment. To change the number of microphones supported,
open the config_files folder and the pdm_pcm_definintions.h file, as shown in
Figure 65 .
Figure 65. pdm_pcm_definitions.h file and USE_SAI2_MIC define
The pdm_pcm_definitions.h header file contains the whole configuration for the SAI data line to use. To switch between three or
two microphones, set the USE_SAI2_MIC to “0U” (two microphones) or “1U” (three microphones). This propagates throughout
the firmware and configures the audio front end.
To switch between two or three microphones, set the USE_SAI2_MIC as follows:
NXP Semiconductors
Far-field local voice control framework
SLN-LOCAL2-IOT Developer’s Guide, Rev. 0, 19 April 2021
User's Guide 51 / 87