Support for "headless", eg. Pico Audio

.github/workflows/cmake.yml

@@ -22,6 +22,9 @@ jobs:
           - name: Galactic Unicorn
             board: galactic
             cmake-args: '-DDISPLAY_PATH=display/galactic/galactic_unicorn.cmake'
+          - name: Headless Unicorn
+            board: none
+            cmake-args: '-DHEADLESS=1'
 
     runs-on: ubuntu-20.04
 

CMakeLists.txt

@@ -12,6 +12,10 @@ set(CMAKE_CXX_STANDARD 17)
 pico_sdk_init()
 
 include(bluetooth/bluetooth.cmake)
+
+if(HEADLESS)
+set(DISPLAY_NAME "Headless Unicorn")
+else()
 include(effect/rainbow_fft.cmake)
 include(effect/classic_fft.cmake)
 
@@ -21,6 +25,8 @@ else()
 message(WARNING "Using default display (display/galactic/galactic_unicorn.cmake)...")
 include(display/galactic/galactic_unicorn.cmake)
 endif()
+endif()
+
 
 add_executable(${NAME}
     ${CMAKE_CURRENT_LIST_DIR}/src/main.cpp
@@ -37,9 +43,6 @@ target_link_libraries(${NAME}
     picow_bt_example_common
     pico_audio_i2s
     pico_multicore
-    display
-    rainbow_fft
-    classic_fft
 )
 
 message(WARNING "Display: ${DISPLAY_NAME}")
@@ -50,6 +53,18 @@ target_compile_definitions(${NAME} PRIVATE
     BLUETOOTH_DEVICE_NAME="${DISPLAY_NAME}"
 )
 
+if(HEADLESS)
+target_compile_definitions(${NAME} PRIVATE
+    HEADLESS=1
+)
+else()
+target_link_libraries(${NAME}
+    display
+    rainbow_fft
+    classic_fft
+)
+endif()
+
 pico_enable_stdio_usb(${NAME} 1)
 pico_add_extra_outputs(${NAME})
 

README.md

@@ -38,4 +38,12 @@ For Cosmic Unicorn:
 mkdir build.cosmic
 cd build.cosmic
 cmake .. -DPICO_SDK_PATH=../../pico-sdk -DPICO_EXTRAS_PATH=../../pico-extras -DPICO_BOARD=pico_w -DDISPLAY_PATH=display/cosmic/cosmic_unicorn.cmake -DCMAKE_BUILD_TYPE=Release
+```
+
+For Pico Audio, ie. without a display:
+
+```bash
+mkdir build.headless
+cd build.headless
+cmake .. -DPICO_SDK_PATH=../../pico-sdk -DPICO_EXTRAS_PATH=../../pico-extras -DPICO_BOARD=none -DHEADLESS=1 -DCMAKE_BUILD_TYPE=Release
 ```

src/a2dp_sink.cpp

@@ -945,7 +945,7 @@ static void stdin_process(char cmd){
 
     switch (cmd){
         case 'b':
-            status = a2dp_sink_establish_stream(device_addr, stream_endpoint->a2dp_local_seid, &a2dp_connection->a2dp_cid);
+            status = a2dp_sink_establish_stream(device_addr, /*stream_endpoint->a2dp_local_seid, */&a2dp_connection->a2dp_cid);
             printf(" - Create AVDTP connection to addr %s, and local seid %d, cid 0x%02x.\n",
                    bd_addr_to_str(device_addr), a2dp_connection->a2dp_local_seid, a2dp_connection->a2dp_cid);
             break;

src/btstack_audio_pico.cpp

@@ -58,6 +58,7 @@
 #include "pico/multicore.h"
 #include "pico/sync.h"
 
+#ifndef HEADLESS
 #include "display.hpp"
 #include "effect.hpp"
 #include "lib/fixed_fft.hpp"
@@ -78,10 +79,28 @@ uint32_t core1_stack[512];
 int16_t effect_buf[SAMPLE_COUNT] = {0};
 #endif
 
+#ifdef EFFECTS_ON_CORE1
+auto_init_mutex(core1_effect_update);
+
+void core1_entry() {
+    while(1) {
+        mutex_enter_blocking(&core1_effect_update);
+        effects[0]->update(effect_buf, SAMPLE_COUNT);
+        mutex_exit(&core1_effect_update);
+    }
+}
+#endif
+
+#else
+// If display is disabled, we'll set the sample count to the same as fixed_fft.hpp does anyway.
+constexpr unsigned int SAMPLE_COUNT = 1024u;
+#define DRIVER_POLL_INTERVAL_MS 5
+
+#endif
+
 static constexpr unsigned int BUFFERS_PER_FFT_SAMPLE = 2;
 static constexpr unsigned int SAMPLES_PER_AUDIO_BUFFER = SAMPLE_COUNT / BUFFERS_PER_FFT_SAMPLE;
 
-
 // client
 static void (*playback_callback)(int16_t * buffer, uint16_t num_samples);
 
@@ -99,18 +118,6 @@ static uint8_t               btstack_audio_pico_channel_count;
 static uint8_t               btstack_volume;
 static uint8_t               btstack_last_sample_idx;
 
-auto_init_mutex(core1_effect_update);
-
-#ifdef EFFECTS_ON_CORE1
-void core1_entry() {
-    while(1) {
-        mutex_enter_blocking(&core1_effect_update);
-        effects[0]->update(effect_buf, SAMPLE_COUNT);
-        mutex_exit(&core1_effect_update);
-    }
-}
-#endif
-
 static audio_buffer_pool_t *init_audio(uint32_t sample_frequency, uint8_t channel_count) {
 
     // num channels requested by application
@@ -147,6 +154,7 @@ static audio_buffer_pool_t *init_audio(uint32_t sample_frequency, uint8_t channe
     assert(ok);
     (void)ok;
 
+#ifndef HEADLESS
     effects.push_back(&rainbow_fft);
     effects.push_back(&classic_fft);
 
@@ -159,6 +167,8 @@ static audio_buffer_pool_t *init_audio(uint32_t sample_frequency, uint8_t channe
 
 #ifdef EFFECTS_ON_CORE1
     multicore_launch_core1_with_stack(core1_entry, core1_stack, core1_stack_len);
+#endif
+
 #endif
 
     return producer_pool;
@@ -171,32 +181,41 @@ static void btstack_audio_pico_sink_fill_buffers(void){
             break;
         }
 
+#ifndef HEADLESS
         if (!gpio_get(Display::SWITCH_A)) {
             current_effect = 0;
         }
 
         if (!gpio_get(Display::SWITCH_B)) {
             current_effect = 1;
         }
+#endif
 
         int16_t * buffer16 = (int16_t *) audio_buffer->buffer->bytes;
         (*playback_callback)(buffer16, audio_buffer->max_sample_count);
 
+#ifndef HEADLESS
 #ifndef EFFECTS_ON_CORE1
         effects[current_effect]->update(buffer16, SAMPLE_COUNT);
 #endif
 
 #ifdef EFFECTS_ON_CORE1
         mutex_enter_blocking(&core1_effect_update);
 #endif
+#endif
+
         for (auto i = 0u; i < SAMPLE_COUNT; i++) {
+#ifndef HEADLESS
 #ifdef EFFECTS_ON_CORE1
             effect_buf[i] = buffer16[i];
+#endif
 #endif
             buffer16[i] = (int32_t(buffer16[i]) * int32_t(btstack_volume)) >> 8;
         }
+#ifndef HEADLESS
 #ifdef EFFECTS_ON_CORE1
         mutex_exit(&core1_effect_update);
+#endif
 #endif
 
         // duplicate samples for mono
@@ -267,7 +286,9 @@ static void btstack_audio_pico_sink_stop_stream(void){
     // state
     btstack_audio_pico_sink_active = false;
 
+#ifndef HEADLESS
     display.clear();
+#endif
 }
 
 static void btstack_audio_pico_sink_close(void){