- 中文版本
- Basic Example:
This example uses the MP3 decoder callback function mp3_music_read_cb to read the MP3 file from the flash. After the data decoding process, the data is output through PWM or DAC.
It should be noted that for ESP32 I2S-DAC output, only GPIO25 and GPIO26 can be used; for PWM output, the GPIOs with output function can be used.
This example runs on the boards that are marked with a green checkbox in the table. Please remember to select the board in menuconfig as discussed in Section Configuration below.
NOTE:
- If PWM output is selected, you need an ESP32 board which has suitable GPIOs exposed to output PWM.
- If I2S-DAC output is selected, you need an ESP32 board that has I2S-DAC pins GPIO25 and GPIO26 exposed.
This example supports IDF release/v3.3 and later branches. By default, it runs on ADF's built-in branch $ADF_PATH/esp-idf.
The default development board selected for this example is ESP32-Lyrat V4.3, and the default music output mode is I2S-DAC, it can be set to PWM mode output in menuconfig.
menuconfig > Example Configuration > Select play mp3 output > Enable PWM outputOnly after the PWM output is enabled can the PWM output pins be configured.
This example selects the two exposed pins I2C_SCK and I2C_SDA on the ESP32-Lyrat V4.3 development board to output the PWM waveform.
menuconfig > Example Configuration > PWM Stream Right Output GPIO NUM > 18menuconfig > Example Configuration > PWM Stream Left Output GPIO NUM > 23Build the project and flash it to the board, then run monitor tool to view serial output (replace PORT with your board's serial port name):
idf.py -p PORT flash monitorTo exit the serial monitor, type Ctrl-].
See the Getting Started Guide for full steps to configure and use ESP-IDF Programming Guide to build projects.
1. PWM output method
Prepare the ESP32 board by connecting GPIO18, GPIO23 and GND pins according to the schematic below. If you use other GPIO, please modify menuconfig.
menuconfig > Example Configuration > Select play mp3 output > Enable PWM outputPWM output method connections:
GPIO18 +--------------+
| __
| / \ _
+-+ | |
| | | | Earphone
+-+ |_|
| \__/
330R |
GND +-------/\/\/\----+
| __
| / \ _
+-+ | |
| | | | Earphone
+-+ |_|
| \__/
|
GPIO23 +--------------+
2. DAC output method
Connect the GPIO25, GPIO26 and GND pins of ESP32 to the earphone according to the figure below. Note that the I2S-DAC output does not support other GPIO pins temporarily.
I2S-DAC output method connections:
GPIO25 +--------------+
| __
| / \ _
+-+ | |
| | | | Earphone
+-+ |_|
| \__/
330R |
GND +-------/\/\/\----+
| __
| / \ _
+-+ | |
| | | | Earphone
+-+ |_|
| \__/
|
GPIO26 +--------------+
A complete log is as follows:
I (66) boot: Chip Revision: 3
I (71) boot_comm: chip revision: 3, min. bootloader chip revision: 0
I (42) boot: ESP-IDF v3.3.2-107-g722043f73 2nd stage bootloader
I (42) boot: compile time 17:07:48
I (42) boot: Enabling RNG early entropy source...
I (48) qio_mode: Enabling default flash chip QIO
I (53) boot: SPI Speed : 80MHz
I (57) boot: SPI Mode : QIO
I (61) boot: SPI Flash Size : 8MB
I (65) boot: Partition Table:
I (69) boot: ## Label Usage Type ST Offset Length
I (76) boot: 0 nvs WiFi data 01 02 00009000 00006000
I (83) boot: 1 phy_init RF data 01 01 0000f000 00001000
I (91) boot: 2 factory factory app 00 00 00010000 00100000
I (98) boot: End of partition table
I (103) boot_comm: chip revision: 3, min. application chip revision: 0
I (110) esp_image: segment 0: paddr=0x00010020 vaddr=0x3f400020 size=0x22174 (139636) map
I (156) esp_image: segment 1: paddr=0x0003219c vaddr=0x3ffb0000 size=0x01ee4 ( 7908) load
I (159) esp_image: segment 2: paddr=0x00034088 vaddr=0x40080000 size=0x00400 ( 1024) load
0x40080000: _WindowOverflow4 at /workshop/audio/esp-adf-internal/esp-idf/components/freertos/xtensa_vectors.S:1779
I (163) esp_image: segment 3: paddr=0x00034490 vaddr=0x40080400 size=0x08f5c ( 36700) load
I (184) esp_image: segment 4: paddr=0x0003d3f4 vaddr=0x00000000 size=0x02c1c ( 11292)
I (187) esp_image: segment 5: paddr=0x00040018 vaddr=0x400d0018 size=0x1ec20 (125984) map
0x400d0018: _flash_cache_start at ??:?
I (230) boot: Loaded app from partition at offset 0x10000
I (230) boot: Disabling RNG early entropy source...
I (231) cpu_start: Pro cpu up.
I (234) cpu_start: Application information:
I (239) cpu_start: Project name: play_mp3_pwm_or_dac
I (245) cpu_start: App version: v2.2-151-g0db7cb28-dirty
I (252) cpu_start: Compile time: Jun 23 2021 17:07:46
I (258) cpu_start: ELF file SHA256: ba34710dd9b2148c...
I (264) cpu_start: ESP-IDF: v3.3.2-107-g722043f73
I (270) cpu_start: Starting app cpu, entry point is 0x40080fac
0x40080fac: call_start_cpu1 at /workshop/audio/esp-adf-internal/esp-idf/components/esp32/cpu_start.c:268
I (0) cpu_start: App cpu up.
I (280) heap_init: Initializing. RAM available for dynamic allocation:
I (287) heap_init: At 3FFAE6E0 len 00001920 (6 KiB): DRAM
I (293) heap_init: At 3FFB2F70 len 0002D090 (180 KiB): DRAM
I (299) heap_init: At 3FFE0440 len 00003AE0 (14 KiB): D/IRAM
I (306) heap_init: At 3FFE4350 len 0001BCB0 (111 KiB): D/IRAM
I (312) heap_init: At 4008935C len 00016CA4 (91 KiB): IRAM
I (318) cpu_start: Pro cpu start user code
I (335) cpu_start: Starting scheduler on PRO CPU.
I (0) cpu_start: Starting scheduler on APP CPU.
I (336) MP3_PWM_DAC_EXAMPLE: [ 1 ] Periph init
I (336) MP3_PWM_DAC_EXAMPLE: [ 2 ] Create audio pipeline for playback
I (346) MP3_PWM_DAC_EXAMPLE: [2.1] Create output stream to write data to codec chip
I (356) MP3_PWM_DAC_EXAMPLE: [2.2] Create wav decoder to decode wav file
I (356) MP3_PWM_DAC_EXAMPLE: [2.3] Register all elements to audio pipeline
I (366) MP3_PWM_DAC_EXAMPLE: [2.4] Link it together [mp3_music_read_cb]-->mp3_decoder-->output_stream-->[codec_chip]
I (376) MP3_PWM_DAC_EXAMPLE: [ 3 ] Set up event listener
I (386) MP3_PWM_DAC_EXAMPLE: [3.1] Listening event from all elements of pipeline
I (396) MP3_PWM_DAC_EXAMPLE: [3.2] Listening event from peripherals
I (396) MP3_PWM_DAC_EXAMPLE: [ 4 ] Start audio_pipeline
I (406) MP3_PWM_DAC_EXAMPLE: [ 5 ] Listen for all pipeline events
I (416) MP3_PWM_DAC_EXAMPLE: [ * ] Receive music info from mp3 decoder, sample_rates=44100, bits=16, ch=2
I (7026) MP3_PWM_DAC_EXAMPLE: [ * ] Stop event received
I (7026) MP3_PWM_DAC_EXAMPLE: [ 6 ] Stop audio_pipeline
E (7026) AUDIO_ELEMENT: [mp3] Element already stopped
E (7026) AUDIO_ELEMENT: [output] Element already stopped
W (7036) AUDIO_PIPELINE: There are no listener registered
W (7036) AUDIO_ELEMENT: [mp3] Element has not create when AUDIO_ELEMENT_TERMINATE
W (7046) AUDIO_ELEMENT: [output] Element has not create when AUDIO_ELEMENT_TERMINATEWhen you use the ESP32-S2 chip and plan to use I2S-DAC to output audio, you will encounter the following compilation errors:
../main/play_mp3_pwm_dac_example.c: In function 'app_main':
/hengyongchao/esp-adf-internal/components/audio_stream/include/i2s_stream.h:91:35: error: 'I2S_MODE_DAC_BUILT_IN' undeclared (first use in this function); did you mean 'I2S_OUT_DATA_BURST_EN'?
.mode = I2S_MODE_MASTER | I2S_MODE_DAC_BUILT_IN | I2S_MODE_TX, \
^~~~~~~~~~~~~~~~~~~~~
../main/play_mp3_pwm_dac_example.c:71:32: note: in expansion of macro 'I2S_STREAM_INTERNAL_DAC_CFG_DEFAULT'
i2s_stream_cfg_t i2s_cfg = I2S_STREAM_INTERNAL_DAC_CFG_DEFAULT();
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~This is because ESP32-S2's I2S does not support DAC output, so in this example ESP32-S2 only has PWM output.
Please use the following feedback channels:
- For technical queries, go to the esp32.com forum
- For a feature request or bug report, create a GitHub issue
We will get back to you as soon as possible.