To enable low-power audio, perform the following steps:
1. Flash boot-imx8mm-m4.img, imx8mm_mcu_demo.img, and vbmeta-imx8mm-m4.img to support audio playback based on
Cortex-M4 FreeRTOS.
2. Add
bootmcu
to
bootcmd
in U-Boot command line, see Section 3.4.2 "Booting with Single MIPI-to-HDMI display and audio
playback based on Cortex-M4 FreeRTOS" in the
Android
™
Quick Start Guide
(AQSUG).
3. Run the following command to enable low-power audio mode:
> su
> setprop vendor.audio.lpa.enable 1
> pkill audioserver
4. Push the .wav audio files to /sdcard/. It is better to use a long duration audio file.
5. Disable the following system sounds:
Settings -> Sound -> Touch sounds
Settings -> Sound -> Screen locking sounds
Settings -> Sound -> Charging sounds
6. Open the DirectAudioPlayer application, and select a file from the spinner. The file selected is listed under the spinner.
7. Click the Play button to play audio.
8. Press the ON/OFF button on the board. The system then enters suspend mode, and the audio can keep playing.
• Only the i.MX 8M Mini EVK board supports this feature. The audio is output from the "LPA output" port on
the audio expansion board. See Figure "i.MX 8M Mini EVK with audio board" in the
Android
™
Quick Start
Guide (AQSUG).
• DirectAudioPlayer supports limited audio files, which is declared in device's audio_policy_configuration.xml
with AUDIO_OUTPUT_FLAG_DIRECT|AUDIO_OUTPUT_FLAG_HW_AV_SYNC flag. Other medias are not
supported. For example, it does not support playing 44100Hz audio.
• DirectAudioPlayer supports 24/32 bits wav file with sampling rates no more than 192000.
NOTE
8.6 How to enable USB 2.0 in U-Boot for i.MX 8QuadXPlus
There are both USB 2.0 and USB 3.0 ports on i.MX 8QuadXPlus MEK board. Because U-Boot can support only one USB gadget
driver, the USB 3.0 port is enabled by default. To use the USB 2.0 port, modify the configurations to enable it and disable the
USB 3.0 gadget driver.
For i.MX 8QuadXPlus MEK, make the following changes under ${MY_ANDROID}/vendor/nxp-opensource/uboot-imx:
diff --git a/configs/imx8qxp_mek_android_defconfig b/configs/imx8qxp_mek_android_defconfig
index ee02e02..e4bbace 100644
--- a/configs/imx8qxp_mek_android_defconfig
+++ b/configs/imx8qxp_mek_android_defconfig
@@ -33,14 +33,14 @@ CONFIG_USB_TCPC=y
CONFIG_CMD_USB_MASS_STORAGE=y
CONFIG_USB_GADGET=y
-# CONFIG_CI_UDC=y
+CONFIG_CI_UDC=y
CONFIG_USB_GADGET_DOWNLOAD=y
CONFIG_USB_GADGET_MANUFACTURER="FSL"
CONFIG_USB_GADGET_VENDOR_NUM=0x18d1
CONFIG_USB_GADGET_PRODUCT_NUM=0x0d02
NXP Semiconductors
Customized Configuration
Android
™
User's Guide, Rev. P9.0.0_2.3.2, 6 March 2020
User's Guide
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