Add mp3 example

Also add channels and bits to i2s output configuration.

Signed-off-by: Paul Guyot <pguyot@kallisys.net>

.github/workflows/build.yml

@@ -2,6 +2,7 @@
 name: Build
 on:
   push:
+    branches: ["main"]
   pull_request:
   workflow_dispatch:
 
@@ -79,6 +80,22 @@ jobs:
         path: AtomVM/src/platforms/esp32/build/atomvm-esp-adf-${{ matrix.soc }}-${{ matrix.idf-version }}.img
         if-no-files-found: error
 
+  build-examples:
+    runs-on: ubuntu-latest
+    container: erlang:26
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Build examples
+        run: |
+          cd examples
+          for conf in  */rebar.config ; do
+            example_dir=`dirname ${conf}`
+            cd ${example_dir}
+            rebar3 atomvm packbeam
+            cd ..
+          done
+
   build-doc:
     runs-on: ubuntu-latest
     container: erlang:26
@@ -120,7 +137,7 @@ jobs:
       - name: Checkout erlfmt
         run: |
             cd ..
-            git clone --depth 1 -b v1.1.0 https://github.com/WhatsApp/erlfmt.git
+            git clone --depth 1 -b v1.3.0 https://github.com/WhatsApp/erlfmt.git
             cd erlfmt
             rebar3 as release escriptize
       - name: Check format with erlfmt

README.md

@@ -1,12 +1,12 @@
-# AtomVM driver for Espressif Audio Framework
+# AtomVM driver for Espressif Audio Development Framework
 
-This component ports [Espressif Audio Framework](https://github.com/espressif/esp-adf)
+This component ports [Espressif Audio Development Framework](https://github.com/espressif/esp-adf)
 to AtomVM, thus enabling audio processing to esp32-based systems powered by
 AtomVM.
 
 [![Build](https://github.com/pguyot/atomvm_esp_adf/actions/workflows/build.yml/badge.svg?branch=main)](https://github.com/pguyot/atomvm_esp_adf/actions/workflows/build.yml)
 
-## Usage:
+## Installation
 
 1. Clone this repository into atomvm/src/platforms/esp32/components with
 the required submodules. You can clone with recursive submodules but most
@@ -23,7 +23,7 @@ git submodule update --init components/esp-adf-libs/
 
 2. Build and flash AtomVM
 
-Espressif Audio Framework requires `CONFIG_FREERTOS_ENABLE_BACKWARD_COMPATIBILITY`
+Espressif Audio Development Framework requires `CONFIG_FREERTOS_ENABLE_BACKWARD_COMPATIBILITY`
 which you can set using the configuration menu or editing sdkconfig file.
 
 You can use a command sequence such as: (port name depends on OS)
@@ -40,30 +40,8 @@ You will also need to flash AtomVM core libraries.
 
 Alternatively, you can flash an image generated by the [CI of this project](https://github.com/pguyot/atomvm_esp_adf/actions/workflows/build.yml).
 
-3. Use `esp_adf_*` modules in your code.
+## Usage
 
-You can refer to [API documentation](https://pguyot.github.io/atomvm_esp_adf/).
+This project defines `esp_adf_*` modules.
 
-```erlang
-AudioPipeline = esp_adf_audio_pipeline:init([]),
-
-MP3File = atomvm:read_priv(?MODULE, "adf_music.mp3"),
-MP3Decoder = esp_adf_mp3_decoder:init([]),
-ok = esp_adf_audio_element:set_read_binary(MP3Decoder, MP3File),
-ok = esp_adf_audio_pipeline:register(AudioPipeline, MP3Decoder, <<"mp3">>),
-
-I2SOutput = esp_adf_i2s_output:init([{gpio_bclk, ?MAX_BCLK_GPIO}, {gpio_lrclk, ?MAX_LRC_GPIO}, {gpio_dout, ?MAX_DIN_GPIO}]),
-ok = esp_adf_audio_pipeline:register(AudioPipeline, I2SOutput, <<"i2s">>),
-
-ok = esp_adf_audio_pipeline:link(AudioPipeline, [<<"mp3">>, <<"i2s">>]),
-
-ok = esp_adf_audio_pipeline:run(AudioPipeline),
-
-...
-
-ok = esp_adf_audio_pipeline:stop(AudioPipeline),
-ok = esp_adf_audio_pipeline:wait_for_stop(AudioPipeline),
-ok = esp_adf_audio_pipeline:terminate(AudioPipeline),
-ok = esp_adf_audio_pipeline:unregister(AudioPipeline, MP3Decoder),
-ok = esp_adf_audio_pipeline:unregister(AudioPipeline, I2SOutput),
-```
+You can refer to [examples](examples/) or [API documentation](https://pguyot.github.io/atomvm_esp_adf/).

examples/play_mp3_i2s/.gitignore

@@ -0,0 +1,20 @@
+.rebar3
+_build
+_checkouts
+_vendor
+.eunit
+*.o
+*.beam
+*.plt
+*.swp
+*.swo
+.erlang.cookie
+ebin
+log
+erl_crash.dump
+.rebar
+logs
+.idea
+*.iml
+rebar3.crashdump
+*~

examples/play_mp3_i2s/README.md

@@ -0,0 +1,20 @@
+play_mp3_i2s
+=====
+
+Sample code to plan an MP3 sound on an I2S card.
+
+It was tested with an esp32c3 card connected to a MAX98357A module.
+
+The MAX98357A module is connected to the following esp32c3 gpios:
+
+- LRCLK: gpio 7
+- BCLK: gpio 6
+- DIN: gpio 5
+
+The MAX98357A module doesn't require any MCLK, so this example doesn't
+configure a gpio for it.
+
+Build and flash
+---------------
+
+    $ rebar3 atomvm esp32_flash -p /dev/cu.usbmodem*

examples/play_mp3_i2s/rebar.config

@@ -0,0 +1,15 @@
+{erl_opts, [debug_info]}.
+{deps, []}.
+
+{shell, [
+    % {config, "config/sys.config"},
+    {apps, [play_mp3_i2s]}
+]}.
+{plugins, [
+    atomvm_rebar3_plugin
+]}.
+{profiles, [
+    {check, [
+        {plugins, [erlfmt]}
+    ]}
+]}.

examples/play_mp3_i2s/rebar.lock

@@ -0,0 +1 @@
+[].

examples/play_mp3_i2s/src/play_mp3_i2s.app.src

@@ -0,0 +1,14 @@
+{application, play_mp3_i2s, [
+    {description, "AtomVM MP3 player"},
+    {vsn, "0.1.0"},
+    {registered, []},
+    {applications, [
+        kernel,
+        stdlib
+    ]},
+    {env, []},
+    {modules, []},
+
+    {licenses, ["MIT"]},
+    {links, []}
+]}.

examples/play_mp3_i2s/src/play_mp3_i2s.erl

@@ -0,0 +1,50 @@
+%%%-------------------------------------------------------------------
+%% @doc Example code to play an MP3 file over i2s
+%% @end
+%%%-------------------------------------------------------------------
+
+-module(play_mp3_i2s).
+
+-export([start/0]).
+
+%% GPIO configuration
+
+-define(I2S_LRC_GPIO, 7).
+-define(I2S_BCLK_GPIO, 6).
+-define(I2S_DIN_GPIO, 5).
+
+start() ->
+    io:format("Play MP3 using AtomVM ESP ADF\n"),
+
+    AudioPipeline = esp_adf_audio_pipeline:init([]),
+
+    MP3File = atomvm:read_priv(?MODULE, "adf_music.mp3"),
+
+    io:format("MP3File: ~B bytes\n", [byte_size(MP3File)]),
+
+    MP3Decoder = esp_adf_mp3_decoder:init([]),
+    ok = esp_adf_audio_element:set_read_binary(MP3Decoder, MP3File),
+    ok = esp_adf_audio_pipeline:register(AudioPipeline, MP3Decoder, <<"mp3">>),
+
+    I2SOutput = esp_adf_i2s_output:init([
+        {rate, 44100},
+        {bits, 16},
+        {gpio_bclk, ?I2S_BCLK_GPIO},
+        {gpio_lrclk, ?I2S_LRC_GPIO},
+        {gpio_dout, ?I2S_DIN_GPIO}
+    ]),
+    ok = esp_adf_audio_pipeline:register(AudioPipeline, I2SOutput, <<"i2s">>),
+
+    ok = esp_adf_audio_pipeline:link(AudioPipeline, [<<"mp3">>, <<"i2s">>]),
+
+    ok = esp_adf_audio_pipeline:run(AudioPipeline),
+
+    timer:sleep(7000),
+
+    ok = esp_adf_audio_pipeline:stop(AudioPipeline),
+    ok = esp_adf_audio_pipeline:wait_for_stop(AudioPipeline),
+    ok = esp_adf_audio_pipeline:terminate(AudioPipeline),
+    ok = esp_adf_audio_pipeline:unregister(AudioPipeline, MP3Decoder),
+    ok = esp_adf_audio_pipeline:unregister(AudioPipeline, I2SOutput),
+
+    ok.

nifs/atomvm_esp_adf_i2s_output.c

@@ -42,6 +42,13 @@ struct I2SData
     i2s_std_config_t std_config;
 };
 
+struct MusicInfo
+{
+    int rate;
+    i2s_slot_mode_t channels;
+    i2s_data_bit_width_t bits;
+};
+
 static esp_err_t i2s_open(audio_element_handle_t self)
 {
     TRACE("%s\n", __func__);
@@ -108,16 +115,16 @@ static int i2s_write(audio_element_handle_t self, char *buffer, int len, TickTyp
     return bytes_written;
 }
 
-static void i2s_data_init(struct I2SData *driver_data, int rate, int gpio_mclk, int gpio_bclk, int gpio_lrclk, int gpio_dout)
+static void i2s_data_init(struct I2SData *driver_data, const struct MusicInfo *music_info, int gpio_mclk, int gpio_bclk, int gpio_lrclk, int gpio_dout)
 {
     TRACE("%s\n", __func__);
 
     driver_data->chan_cfg = (i2s_chan_config_t) I2S_CHANNEL_DEFAULT_CONFIG(I2S_NUM_AUTO, I2S_ROLE_MASTER);
     i2s_new_channel(&driver_data->chan_cfg, &driver_data->tx_handle, NULL);
 
     driver_data->std_config = (i2s_std_config_t){
-        .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(rate),
-        .slot_cfg = I2S_STD_MSB_SLOT_DEFAULT_CONFIG(I2S_DATA_BIT_WIDTH_32BIT, I2S_SLOT_MODE_STEREO),
+        .clk_cfg = I2S_STD_CLK_DEFAULT_CONFIG(music_info->rate),
+        .slot_cfg = I2S_STD_PHILIPS_SLOT_DEFAULT_CONFIG(music_info->bits, music_info->channels),
         .gpio_cfg = {
             .mclk = gpio_mclk,
             .bclk = gpio_bclk,
@@ -134,7 +141,7 @@ static void i2s_data_init(struct I2SData *driver_data, int rate, int gpio_mclk,
     i2s_channel_init_std_mode(driver_data->tx_handle, &driver_data->std_config);
 }
 
-static term i2s_output_new(Context *ctx, term argv[], int rate, int gpio_mclk, int gpio_bclk, int gpio_lrclk, int gpio_dout)
+static term i2s_output_new(Context *ctx, term argv[], const struct MusicInfo *music_info, int gpio_mclk, int gpio_bclk, int gpio_lrclk, int gpio_dout)
 {
     TRACE("%s\n", __func__);
 
@@ -165,7 +172,7 @@ static term i2s_output_new(Context *ctx, term argv[], int rate, int gpio_mclk, i
         RAISE_ERROR(OUT_OF_MEMORY_ATOM);
     }
 
-    i2s_data_init(driver_data, rate, gpio_mclk, gpio_bclk, gpio_lrclk, gpio_dout);
+    i2s_data_init(driver_data, music_info, gpio_mclk, gpio_bclk, gpio_lrclk, gpio_dout);
 
     rsrc_obj->audio_element = audio_element_init(&cfg);
     if (IS_NULL_PTR(rsrc_obj->audio_element)) {
@@ -175,6 +182,7 @@ static term i2s_output_new(Context *ctx, term argv[], int rate, int gpio_mclk, i
     }
 
     audio_element_setdata(rsrc_obj->audio_element, driver_data);
+    audio_element_set_music_info(rsrc_obj->audio_element, music_info->rate, music_info->channels, music_info->bits);
 
     return obj;
 }
@@ -188,19 +196,16 @@ static term nif_init(Context *ctx, int argc, term argv[])
 
     VALIDATE_VALUE(cfg, term_is_list);
 
-    term rate_term = interop_kv_get_value_default(cfg, ATOM_STR("\x4", "rate"), term_from_int(48000), ctx->global);
     term gpio_mclk_term = interop_kv_get_value_default(cfg, ATOM_STR("\x9", "gpio_mclk"), term_from_int(I2S_GPIO_UNUSED), ctx->global);
     term gpio_bclk_term = interop_kv_get_value(cfg, ATOM_STR("\x9", "gpio_bclk"), ctx->global);
     term gpio_lrclk_term = interop_kv_get_value(cfg, ATOM_STR("\xA", "gpio_lrclk"), ctx->global);
     term gpio_dout_term = interop_kv_get_value(cfg, ATOM_STR("\x9", "gpio_dout"), ctx->global);
 
-    VALIDATE_VALUE(rate_term, term_is_integer);
     VALIDATE_VALUE(gpio_mclk_term, term_is_integer);
     VALIDATE_VALUE(gpio_bclk_term, term_is_integer);
     VALIDATE_VALUE(gpio_lrclk_term, term_is_integer);
     VALIDATE_VALUE(gpio_dout_term, term_is_integer);
 
-    avm_int_t rate = term_to_int(rate_term);
     avm_int_t gpio_mclk = term_to_int(gpio_mclk_term);
     avm_int_t gpio_bclk = term_to_int(gpio_bclk_term);
     avm_int_t gpio_lrclk = term_to_int(gpio_lrclk_term);
@@ -219,7 +224,42 @@ static term nif_init(Context *ctx, int argc, term argv[])
         RAISE_ERROR(BADARG_ATOM);
     }
 
-    return i2s_output_new(ctx, argv, rate, gpio_mclk, gpio_bclk, gpio_lrclk, gpio_dout);
+    term rate_term = interop_kv_get_value_default(cfg, ATOM_STR("\x4", "rate"), term_from_int(48000), ctx->global);
+    term bits_term = interop_kv_get_value_default(cfg, ATOM_STR("\x4", "bits"), term_from_int(32), ctx->global);
+    term channels_term = interop_kv_get_value_default(cfg, ATOM_STR("\x8", "channels"), term_from_int(2), ctx->global);
+
+    VALIDATE_VALUE(rate_term, term_is_integer);
+    VALIDATE_VALUE(bits_term, term_is_integer);
+    VALIDATE_VALUE(channels_term, term_is_integer);
+
+    avm_int_t rate = term_to_int(rate_term);
+    avm_int_t bits = term_to_int(bits_term);
+    avm_int_t channels = term_to_int(channels_term);
+
+    // In standard mode, there are always 2 channels
+    if (UNLIKELY(channels != 2)) {
+        RAISE_ERROR(BADARG_ATOM);
+    }
+    // In standard mode, bits can be 8/16/24 or 32
+    if (UNLIKELY(bits != 8 && bits != 16 && bits != 24 && bits != 32)) {
+        RAISE_ERROR(BADARG_ATOM);
+    }
+
+#if __STDC_VERSION__ >= 201112L
+    _Static_assert(I2S_SLOT_MODE_STEREO == 2, "expected I2S_SLOT_MODE_STEREO to be equal to 2");
+    _Static_assert(I2S_DATA_BIT_WIDTH_8BIT == 8, "expected I2S_DATA_BIT_WIDTH_8BIT to be equal to 8");
+    _Static_assert(I2S_DATA_BIT_WIDTH_16BIT == 16, "expected I2S_DATA_BIT_WIDTH_16BIT to be equal to 16");
+    _Static_assert(I2S_DATA_BIT_WIDTH_24BIT == 24, "expected I2S_DATA_BIT_WIDTH_24BIT to be equal to 24");
+    _Static_assert(I2S_DATA_BIT_WIDTH_32BIT == 32, "expected I2S_DATA_BIT_WIDTH_32BIT to be equal to 32");
+#endif
+
+    struct MusicInfo music_info = {
+        .rate = rate,
+        .bits = bits,
+        .channels = channels
+    };
+
+    return i2s_output_new(ctx, argv, &music_info, gpio_mclk, gpio_bclk, gpio_lrclk, gpio_dout);
 }
 
 static const struct Nif init_nif = {

rebar.config

@@ -1,3 +1,8 @@
 {erl_opts, [debug_info]}.
 {deps, []}.
 {plugins, [atomvm_rebar3_plugin]}.
+{profiles, [
+    {check, [
+        {plugins, [erlfmt]}
+    ]}
+]}.

src/atomvm_esp_adf.app.src

@@ -4,7 +4,7 @@
         {vsn, "0.1.0"},
         {registered, []},
         {applications, [kernel, stdlib]},
-        {env,[]},
+        {env, []},
         {modules, []},
         {licenses, ["MIT"]},
         {links, []}

src/esp_adf_i2s_output.erl

@@ -5,13 +5,17 @@
 
 -type i2s_output_option() ::
     {rate, pos_integer()}
+    | {bits, 8 | 16 | 24 | 32}
+    | {channels, 1 | 2}
     | {gpio_mclk, -1 | non_neg_integer()}
     | {gpio_bclk, non_neg_integer()}
     | {gpio_lrclk, non_neg_integer()}
     | {gpio_dout, non_neg_integer()}.
 
 %% @doc Create a handle to an i2s output audio element.
 %% `gpio_bclk', `gpio_lrclk' and `gpio_dout' options are required.
+%% I2S is configured in standard mode ("Philips"), which means that
+%% channels should be 2 (this is the default) and bits can be 8, 16, 24 or 32.
 %% @param Cfg configuration
 -spec init([i2s_output_option()]) -> audio_element:audio_element().
 init(_Cfg) ->