Allow audio underrun (#1)

* Allow audio underrun

* HDMI audio

* Allow audio underrun

* Allow audio underrun

software/apps/colour_terminal_audio/CMakeLists.txt

@@ -21,5 +21,7 @@ target_link_libraries(colour_terminal_audio
 	libdvi
 )
 
+# pico_enable_stdio_uart(colour_terminal_audio 1)
+
 # create map/bin/hex file etc.
 pico_add_extra_outputs(colour_terminal_audio)

software/apps/colour_terminal_audio/main.c

@@ -86,23 +86,22 @@ audio_sample_t      audio_buffer[AUDIO_BUFFER_SIZE];
 struct repeating_timer audio_timer;
 
 bool audio_timer_callback(struct repeating_timer *t) {
-    int size = get_write_size(&dvi0.audio_ring, false);
-    audio_sample_t *audio_ptr = get_write_pointer(&dvi0.audio_ring);
-    audio_sample_t sample;
-    static uint sample_count = 0;
-    for (int cnt = 0; cnt < size; cnt++) {
-        sample.channels[0] = commodore_argentina[sample_count % commodore_argentina_len] << 8;
-        sample.channels[1] = commodore_argentina[(sample_count+1024) % commodore_argentina_len] << 8;
-        *audio_ptr++ = sample;
-        sample_count = sample_count + 1;
-    }
-    increase_write_pointer(&dvi0.audio_ring, size);
-
- 
-    return true;
+	while(true) {
+		int size = get_write_size(&dvi0.audio_ring, false);
+		if (size == 0) return true;
+		audio_sample_t *audio_ptr = get_write_pointer(&dvi0.audio_ring);
+		audio_sample_t sample;
+		static uint sample_count = 0;
+		for (int cnt = 0; cnt < size; cnt++) {
+			sample.channels[0] = commodore_argentina[sample_count % commodore_argentina_len] << 8;
+			sample.channels[1] = commodore_argentina[(sample_count+1024) % commodore_argentina_len] << 8;
+			*audio_ptr++ = sample;
+			sample_count = sample_count + 1;
+		}
+		increase_write_pointer(&dvi0.audio_ring, size);
+	}
 }
 
-
 // Pixel format RGB222
 static inline void set_colour(uint x, uint y, uint8_t fg, uint8_t bg) {
 	if (x >= CHAR_COLS || y >= CHAR_ROWS)
@@ -146,6 +145,8 @@ int __not_in_flash("main") main() {
 	// Run system at TMDS bit clock
 	set_sys_clock_khz(DVI_TIMING.bit_clk_khz, true);
 
+    // setup_default_uart();
+
 	dvi0.timing = &DVI_TIMING;
 	dvi0.ser_cfg = DVI_DEFAULT_SERIAL_CONFIG;
 	dvi_init(&dvi0, next_striped_spin_lock_num(), next_striped_spin_lock_num());
@@ -166,6 +167,8 @@ int __not_in_flash("main") main() {
     dvi_set_audio_freq(&dvi0, 44100, 28000, 6272);
     add_repeating_timer_ms(-2, audio_timer_callback, NULL, &audio_timer);
 
+	printf("starting...\n");
+
 	multicore_launch_core1(core1_main);
 
 	while (1)

software/apps/mandelbrot/main.c

@@ -26,14 +26,14 @@
 struct dvi_inst dvi0;
 uint16_t framebuf[FRAME_WIDTH * FRAME_HEIGHT];
 
-void core1_main() {
+void __not_in_flash_func(core1_main)() {
 	dvi_register_irqs_this_core(&dvi0, DMA_IRQ_0);
 	dvi_start(&dvi0);
 	dvi_scanbuf_main_16bpp(&dvi0);
 	__builtin_unreachable();
 }
 
-void core1_scanline_callback() {
+void __not_in_flash_func(core1_scanline_callback)() {
 	// Discard any scanline pointers passed back
 	uint16_t *bufptr;
 	while (queue_try_remove_u32(&dvi0.q_colour_free, &bufptr))
@@ -45,7 +45,7 @@ void core1_scanline_callback() {
 	scanline = (scanline + 1) % FRAME_HEIGHT;
 }
 
-int main() {
+int __not_in_flash_func(main)() {
 	vreg_set_voltage(VREG_VSEL);
 	sleep_ms(10);
 #ifdef RUN_FROM_CRYSTAL

software/apps/terminal/main.c

@@ -73,7 +73,7 @@ struct semaphore dvi_start_sem;
 #define CHAR_ROWS (FRAME_HEIGHT / FONT_CHAR_HEIGHT)
 char charbuf[CHAR_ROWS * CHAR_COLS];
 
-static inline void prepare_scanline(const char *chars, uint y) {
+static inline void __not_in_flash_func(prepare_scanline)(const char *chars, uint y) {
 	static uint8_t scanbuf[FRAME_WIDTH / 8];
 	// First blit font into 1bpp scanline buffer, then encode scanbuf into tmdsbuf
 	for (uint i = 0; i < CHAR_COLS; ++i) {
@@ -86,13 +86,13 @@ static inline void prepare_scanline(const char *chars, uint y) {
 	queue_add_blocking(&dvi0.q_tmds_valid, &tmdsbuf);
 }
 
-void core1_scanline_callback() {
+void __not_in_flash_func(core1_scanline_callback)() {
 	static uint y = 1;
 	prepare_scanline(charbuf, y);
 	y = (y + 1) % FRAME_HEIGHT;
 }
 
-void __not_in_flash("main") core1_main() {
+void __not_in_flash_func(core1_main)() {
 	dvi_register_irqs_this_core(&dvi0, DMA_IRQ_0);
 	sem_acquire_blocking(&dvi_start_sem);
 	dvi_start(&dvi0);
@@ -104,7 +104,7 @@ void __not_in_flash("main") core1_main() {
 	__builtin_unreachable();
 }
 
-int __not_in_flash("main") main() {
+int __not_in_flash_func(main)() {
 	vreg_set_voltage(VREG_VSEL);
 	sleep_ms(10);
 #ifdef RUN_FROM_CRYSTAL

software/include/common_dvi_pin_configs.h

@@ -61,16 +61,16 @@ static const struct dvi_serialiser_cfg micromod_cfg = {
 };
 
 // Pico DVI Sock (small hat on the bottom) which solders to the end of a Pico
-// static const struct dvi_serialiser_cfg pico_sock_cfg = {
-// 	.pio = DVI_DEFAULT_PIO_INST,
-// 	.sm_tmds = {0, 1, 2},
-// 	.pins_tmds = {12, 18, 16},
-// 	.pins_clk = 14,
-// 	.invert_diffpairs = false
-// };
+static const struct dvi_serialiser_cfg pico_sock_cfg = {
+	.pio = DVI_DEFAULT_PIO_INST,
+	.sm_tmds = {0, 1, 2},
+	.pins_tmds = {12, 18, 16},
+	.pins_clk = 14,
+	.invert_diffpairs = false
+};
 
 // pico-RGB2HDMI
-static const struct dvi_serialiser_cfg pico_sock_cfg = {
+static const struct dvi_serialiser_cfg pico_rgb2hdmi_cfg = {
         .pio = pio0,
         .sm_tmds = {0, 1, 2},
         .pins_tmds = {5, 7, 9},

software/libdvi/data_packet.c

@@ -206,7 +206,7 @@ void __not_in_flash_func(set_null)(void *data, int size) {
     }
 }
 
-int  __not_in_flash_func(set_audio_sample)(data_packet_t *data_packet, const audio_sample_t *p, int n, int frameCt) {
+int  __not_in_flash_func(set_audio_sample)(data_packet_t *data_packet, audio_ring_t *audio_ring, const int n, int frameCt) {
     const int layout = 0;
     const int samplePresent = (1 << n) - 1;
     const int B = (frameCt < n) ? (1 << frameCt) : 0;
@@ -214,24 +214,34 @@ int  __not_in_flash_func(set_audio_sample)(data_packet_t *data_packet, const aud
     data_packet->header[1] = (layout << 4) | samplePresent;
     data_packet->header[2] = B << 4;
     compute_header_parity(data_packet);
+    const int read_size = get_read_size(audio_ring, true);
 
     for (int i = 0; i < n; ++i)
     {
-        uint8_t *d = data_packet->subpacket[i];
-        const int16_t l = (*p).channels[0];
-        const int16_t r = (*p).channels[1];
+        int16_t l, r;
+        if (i < read_size) {
+            audio_sample_t *audio_sample_ptr = get_read_pointer(audio_ring);
+            l = (*audio_sample_ptr).channels[0];
+            r = (*audio_sample_ptr).channels[1];
+            increase_read_pointer(audio_ring, 1);
+        }
+        else {
+            l = (int16_t)0;
+            r = (int16_t)0;
+        }
+
         const uint8_t vuc = 1; // valid
+        uint8_t *d = data_packet->subpacket[i];
         d[0] = 0;
         d[1] = l;
         d[2] = l >> 8;
         d[3] = 0;
         d[4] = r;
         d[5] = r >> 8;
-        ++p;
         bool pl = compute8_3(d[1], d[2], vuc);
         bool pr = compute8_3(d[4], d[5], vuc);
         d[6] = (vuc << 0) | (pl << 3) | (vuc << 4) | (pr << 7);
-        compute_subpacket_parity(data_packet, i);
+        d[7] = encode_BCH_7(d);
 
         // channel status (is it relevant?)
         // After testing, seems better to ignore

software/libdvi/data_packet.h

@@ -85,7 +85,7 @@ void compute_info_frame_checkSum(data_packet_t *data_packet);
 void encode_header(const data_packet_t *data_packet, uint32_t *dst, int hv, bool firstPacket);
 void encode_subpacket(const data_packet_t *data_packet, uint32_t *dst1, uint32_t *dst2);
 void set_null(void *data, int size);
-int  set_audio_sample(data_packet_t *data_packet, const audio_sample_t *p, int n, int frameCt);
+int  set_audio_sample(data_packet_t *data_packet, audio_ring_t *audio_ring, const int n, int frameCt);
 void set_audio_clock_regeneration(data_packet_t *data_packet, int CTS, int N);
 void set_audio_info_frame(data_packet_t *data_packet, int freq);
 void set_AVI_info_frame(data_packet_t *data_packet, scan_info s, pixel_format y, colorimetry c, picture_aspect_ratio m,

software/libdvi/dvi.c

@@ -412,16 +412,12 @@ bool __dvi_func(dvi_update_data_packet_)(struct dvi_inst *inst, data_packet_t *p
             return true;
         }
     }
-    int sample_pos_24 = inst->audio_sample_pos >> 24;
-    int read_size = get_read_size(&inst->audio_ring, false);
-    int n = MIN(4, MIN(sample_pos_24, read_size));
-    inst->audio_sample_pos -= (n << 24);
+    const int sample_pos_24 = inst->audio_sample_pos >> 24;
+    const int n = MIN(4, sample_pos_24);
     if (n)
     {
-        audio_sample_t *audio_sample_ptr = get_read_pointer(&inst->audio_ring);
-        inst->audio_frame_count = set_audio_sample(packet, audio_sample_ptr, n, inst->audio_frame_count);
-        increase_read_pointer(&inst->audio_ring, n);
-
+        inst->audio_sample_pos -= (n << 24);
+        inst->audio_frame_count = set_audio_sample(packet, &inst->audio_ring, n, inst->audio_frame_count);
         return true;
     }