The logical understanding of sound source switching in car development:
(1) First of all, you must know: the ARM hardware sound channel is directly connected to the sound effect chip, and then the I2C of the MCU chip controls the sound source module that is switched on by the sound effect chip
(2) Then Need to know: the sound source module is not only ARM, but also independent hardware chips such as Aux_in (DVD video input), Radio (radio sound input), mobile phone interconnection, Bluetooth and other independent hardware chips that directly input sound to the sound effect chip, but only by The MCU controls which sound source module the sound effect chip switches to. The sound effect chip is like a single-pole multi-throw switch, and whoever hits it will make the sound; the sound of the mobile phone interconnection is actually transmitted through Bluetooth, and it must be connected to Bluetooth. It can transmit the sound on the mobile phone interconnection app to the sound effect chip. It is not an independent sound source module, but is essentially the sound source module of Bluetooth. After all, it is just an app on the mobile phone, not an independent hardware module; But when it comes to bluetooth module, bluetooth module may be built-in bluetooth or external bluetooth. Built-in bluetooth means that the S700_ARM main chip integrates the function of bluetooth module, and the control function is the corresponding system setting apk application, but most of our companies generally have It is an external bluetooth module. Our company has used Suding and Wenqiang bluetooth modules. The bluetooth sound of the Suding module directly goes through the module, not ARM, but the Wenqiang bc6 bluetooth module uses the ARM media audio channel for bluetooth music. Voices such as incoming and outgoing calls go through the ARM's VOICE_CALL channel;
(3) There are two types of voice switching: the switching of the sound source module is the switching of the hardware channel, and the voice switching in the ARM Android system is the switching of the software channel, and the ARM's voice switching is the switching of the software channel. Sound is just one of the hardware sound channels;
(4) When we develop the S700 whole machine project, we need to switch the sound hardware. For example, when opening the radio apk application Activity interface, we send the MCU command to switch the sound effect channel to the radio chip. For the protocol, please refer to the mcu protocol document, Activity When the interface is destroyed, send the MCU command to switch the sound effect channel back to ARM. The command code sent is mcuManager.mcuSourceChange(0x51); 0X51 may be a newly added command, which is not mentioned in the mcu protocol document. ;
(1) First of all, you must know: the ARM hardware sound channel is directly connected to the sound effect chip, and then the I2C of the MCU chip controls the sound source module that is switched on by the sound effect chip
(2) Then Need to know: the sound source module is not only ARM, but also independent hardware chips such as Aux_in (DVD video input), Radio (radio sound input), mobile phone interconnection, Bluetooth and other independent hardware chips that directly input sound to the sound effect chip, but only by The MCU controls which sound source module the sound effect chip switches to. The sound effect chip is like a single-pole multi-throw switch, and whoever hits it will make the sound; the sound of the mobile phone interconnection is actually transmitted through Bluetooth, and it must be connected to Bluetooth. It can transmit the sound on the mobile phone interconnection app to the sound effect chip. It is not an independent sound source module, but is essentially the sound source module of Bluetooth. After all, it is just an app on the mobile phone, not an independent hardware module; But when it comes to bluetooth module, bluetooth module may be built-in bluetooth or external bluetooth. Built-in bluetooth means that the S700_ARM main chip integrates the function of bluetooth module, and the control function is the corresponding system setting apk application, but most of our companies generally have It is an external bluetooth module. Our company has used Suding and Wenqiang bluetooth modules. The bluetooth sound of the Suding module directly goes through the module, not ARM, but the Wenqiang bc6 bluetooth module uses the ARM media audio channel for bluetooth music. Voices such as incoming and outgoing calls go through the ARM's VOICE_CALL channel;
(3) There are two types of voice switching: the switching of the sound source module is the switching of the hardware channel, and the voice switching in the ARM Android system is the switching of the software channel, and the ARM's voice switching is the switching of the software channel. Sound is just one of the hardware sound channels;
(4) When we develop the S700 whole machine project, we need to switch the sound hardware. For example, when opening the radio apk application Activity interface, we send the MCU command to switch the sound effect channel to the radio chip. For the protocol, please refer to the mcu protocol document, Activity When the interface is destroyed, send the MCU command to switch the sound effect channel back to ARM. The command code sent is mcuManager.mcuSourceChange(0x51); 0X51 may be a newly added command, which is not mentioned in the mcu protocol document. ;
(5) When we click on the third-party apk that involves sound, then we also need to send the 0X51 command to switch to the ARM channel;
Note: Please refer to your own project for the above platform, hardware and protocol content, but the basic framework should remain unchanged, because there are only a few sound sources in the Android development of the car