There's audio, but it's glitched.

it only works at all with 128k or 256k non-psram builds

you can hear the beep when you adjust the slider in control panel, but
there's other audio overlaid on it that is kind of a weird descending tone,
very regular in nature.

The sample rate is set to 20k not 22.255k because of my i2s dac not
liking random sample rates.

Instead of using the i2s dac on the fruit jam, this uses A0 (data),
A1 (lrck), A2 (bclk). It's not super convenient, and it's hard coded.

CMakeLists.txt

@@ -62,6 +62,9 @@ set(PSRAM_CS 47 CACHE STRING "PSRAM Chip select pin")
 set(PIN_USB_HOST_DP 1 CACHE STRING "USB D+ PIN")
 set(PIN_USB_HOST_DM 2 CACHE STRING "USB D- PIN")
 
+set(USE_AUDIO 1 CACHE STRING "Use audio")
+set(PIN_AUDIO_PWM 41 CACHE STRING "Pin for PWM audio")
+
 # See below, -DMEMSIZE=<size in KB> will configure umac's memory size,
 # overriding defaults.
 
@@ -136,6 +139,14 @@ else()
   add_compile_definitions(USE_PSRAM=0)
 endif()
 
+if (USE_AUDIO)
+   add_subdirectory(external/pico-extras/src/rp2_common/pico_audio_i2s)
+   add_subdirectory(external/pico-extras/src/common/pico_audio)
+   add_subdirectory(external/pico-extras/src/common/pico_util_buffer)
+   add_compile_definitions(ENABLE_AUDIO=1 PICO_AUDIO_I2S_PIO=1 PICO_AUDIO_I2S_DMA_IRQ=0 PICO_AUDIO_I2S_DATA_PIN=40 PICO_AUDIO_I2S_CLOCK_PIN_BASE=41)
+   set(EXTRA_AUDIO_LIB pico_util_buffer pico_audio pico_audio_i2s)
+endif()
+
 if (TARGET tinyusb_device)
   add_executable(firmware
     src/main.c
@@ -171,6 +182,7 @@ if (TARGET tinyusb_device)
     hardware_pio
     hardware_sync
     ${EXTRA_SD_LIB}
+    ${EXTRA_AUDIO_LIB}
     )
 
   target_include_directories(firmware PRIVATE

external/pico-extras

@@ -1 +1 @@
-Subproject commit 8606fb88057873154f9b6f98a3e52e233cd988d9
+Subproject commit 0b7be7c7fcc6346f6160e96ec73f940a4d403713

external/umac

@@ -1 +1 @@
-Subproject commit 0be2290d4a2176938925075eb33cfd9b1a50aab6
+Subproject commit 4dea595da2d3c616a3ac8bb7031191bbeca85b0d

fruitjam-build.sh

@@ -39,6 +39,8 @@ while getopts "hvd:m:" o; do
     esac
 done
 
+shift $((OPTIND-1))
+
 TAG=fruitjam_${DISP_WIDTH}x${DISP_HEIGHT}_${MEMSIZE}k
 PSRAM=$((MEMSIZE > 448 || DISP_WIDTH < 640))
 if [ $PSRAM -ne 0 ] ; then
@@ -71,5 +73,5 @@ cmake -S . -B build_${TAG} \
     -DMEMSIZE=${MEMSIZE} \
     -DUSE_HSTX=1 \
     -DSD_TX=35 -DSD_RX=36 -DSD_SCK=34 -DSD_CS=39 -DUSE_SD=1 \
-    ${CMAKE_ARGS}
+    ${CMAKE_ARGS} "$@"
 make -C build_${TAG} -j$(nproc)

src/main.c

@@ -57,6 +57,14 @@
 #include "hardware/structs/qmi.h"
 #include "hardware/structs/xip.h"
 #endif
+
+#if ENABLE_AUDIO
+#include "pico/audio_i2s.h"
+uint8_t *audio_base;
+static void audio_setup();
+static bool audio_poll();
+#endif
+
 ////////////////////////////////////////////////////////////////////////////////
 // Imports and data
 
@@ -97,8 +105,8 @@ static void     poll_led_etc()
         if (absolute_time_diff_us(last, now) > 500*1000) {
                 last = now;
 
-                led_on ^= 1;
-                gpio_put(GPIO_LED_PIN, led_on);
+                //led_on ^= 1;
+                //gpio_put(GPIO_LED_PIN, led_on);
         }
 }
 
@@ -126,11 +134,6 @@ static void copy_framebuffer() {
           *dest++ = *src++ ^ 0xfffffffful;
         }
     }
-    uint16_t *src16 = (uint16_t*)(umac_ram + umac_get_audio_offset());
-    for(int i=0; i<370; i++) {
-        uint32_t *dest = umac_framebuffer_mirror + LONGS_PER_OUTPUT_ROW * i;
-        *dest = *src16++;
-    }
 #else
 #error Unsupported display geometry for framebuffer mirroring
 #endif
@@ -147,7 +150,11 @@ static void     poll_umac()
 
         int64_t p_1hz = absolute_time_diff_us(last_1hz, now);
         int64_t p_vsync = absolute_time_diff_us(last_vsync, now);
-        if (p_vsync >= 16667) {
+        bool pending_vsync = p_vsync > 16667;
+#if ENABLE_AUDIO
+        pending_vsync |= audio_poll();
+#endif
+        if (pending_vsync) {
 #if USE_PSRAM
                 copy_framebuffer();
 #endif
@@ -305,6 +312,9 @@ static void     core1_main()
         video_init((uint32_t *)(umac_ram + umac_get_fb_offset()));
 #endif
 
+#if ENABLE_AUDIO
+        audio_base = (uint8_t*)umac_ram + umac_get_audio_offset();
+#endif
         printf("Enjoyable Mac times now begin:\n\n");
 
         while (true) {
@@ -464,6 +474,10 @@ int     main()
 	stdio_init_all();
         io_init();
 
+#if ENABLE_AUDIO
+        audio_setup();
+#endif
+
         multicore_launch_core1(core1_main);
 
 	printf("Starting, init usb\n");
@@ -494,3 +508,77 @@ int     main()
 	return 0;
 }
 
+#if ENABLE_AUDIO
+static int volscale;
+
+
+#define SAMPLES_PER_BUFFER (370)
+int16_t audio[SAMPLES_PER_BUFFER];
+
+void umac_audio_trap() {
+static int led_on;
+                led_on ^= 1;
+                gpio_put(GPIO_LED_PIN, 1);
+    int32_t  offset = 128;
+    uint16_t *audiodata = (uint16_t*)audio_base;
+    int scale = volscale;
+    if (!scale) {
+        memset(audio, 0, sizeof(audio));
+        return;
+    }
+    int16_t *stream = audio;
+    for(int i=0; i<SAMPLES_PER_BUFFER; i++) {
+        int32_t a = (*audiodata++ & 0xff) - offset; 
+        a = (a * scale) >> 8;
+        *stream++ = a;
+    }
+}
+
+struct audio_buffer_pool *producer_pool;
+
+static audio_format_t audio_format = {
+        .format = AUDIO_BUFFER_FORMAT_PCM_S16,
+        .sample_freq = 20000,
+        .channel_count = 1,
+};
+
+const struct audio_i2s_config config =
+        {
+            .data_pin = PICO_AUDIO_I2S_DATA_PIN,
+            .clock_pin_base = PICO_AUDIO_I2S_CLOCK_PIN_BASE,
+            .pio_sm = 0,
+            .dma_channel = 3
+        };
+
+static struct audio_buffer_format producer_format = {
+        .format = &audio_format,
+        .sample_stride = 2
+};
+
+static void audio_setup() {
+    const struct audio_format *output_format = audio_i2s_setup(&audio_format, &config);
+    assert(output_format);
+    if (!output_format) {
+        panic("PicoAudio: Unable to open audio device.\n");
+    }
+    producer_pool = audio_new_producer_pool(&producer_format, 3, SAMPLES_PER_BUFFER);
+    assert(producer_pool);
+    bool ok = audio_i2s_connect(producer_pool);
+    assert(ok);
+    audio_i2s_set_enabled(true);
+}
+
+static bool audio_poll() {
+    audio_buffer_t *buffer = take_audio_buffer(producer_pool, false);
+    if (!buffer) return false;
+                gpio_put(GPIO_LED_PIN, 0);
+    memcpy(buffer->buffer->bytes, audio, sizeof(audio));
+    buffer->sample_count = SAMPLES_PER_BUFFER;
+    give_audio_buffer(producer_pool, buffer);
+    return true;
+}
+
+void umac_audio_cfg(int volume, int sndres) {
+    volscale = sndres ? 0 : 65536 * volume / 7;
+}
+#endif

src/video_hstx.c

@@ -300,10 +300,10 @@ void    video_init(uint32_t *framebuffer) {
         false
         );
 
-    dma_hw->ints0 = (1u << self->dma_pixel_channel);
-    dma_hw->inte0 = (1u << self->dma_pixel_channel);
-    irq_set_exclusive_handler(DMA_IRQ_0, dma_irq_handler);
-    irq_set_enabled(DMA_IRQ_0, true);
+    dma_hw->ints2 = (1u << self->dma_pixel_channel);
+    dma_hw->inte2 = (1u << self->dma_pixel_channel);
+    irq_set_exclusive_handler(DMA_IRQ_2, dma_irq_handler);
+    irq_set_enabled(DMA_IRQ_2, true);
 
     bus_ctrl_hw->priority = BUSCTRL_BUS_PRIORITY_DMA_W_BITS | BUSCTRL_BUS_PRIORITY_DMA_R_BITS;