add API for playing sounds from the buzzer

7 files changed, 483 insertions, 3 deletions

diff --git a/Sensor Watch Buzzer Demo/app.c b/Sensor Watch Buzzer Demo/app.c
new file mode 100644
index 00000000..5c2dbc7b
--- /dev/null
+++ b/Sensor Watch Buzzer Demo/app.c
@@ -0,0 +1,137 @@
+#include <stdio.h>
+#include <string.h>
+#include "watch.h"
+
+typedef struct ApplicationState {
+    bool play;
+    bool debounce_wait;
+} ApplicationState;
+
+ApplicationState application_state;
+
+
+void cb_alarm_pressed() {
+    if (application_state.debounce_wait) return;
+    application_state.debounce_wait = true;
+    application_state.play = true;
+}
+
+void app_init() {
+    memset(&application_state, 0, sizeof(application_state));
+}
+
+void app_wake_from_deep_sleep() {
+}
+
+void app_setup() {
+    watch_register_button_callback(BTN_ALARM, cb_alarm_pressed);
+
+    watch_enable_display();
+
+    watch_enable_buzzer();
+}
+
+void app_prepare_for_sleep() {
+    watch_display_string("  rains ", 2);
+}
+
+void app_wake_from_sleep() {
+}
+
+bool app_loop() {
+    if (application_state.play) {
+        const BuzzerNote rains[] = {
+            BUZZER_NOTE_A4,
+            BUZZER_NOTE_F5,
+            BUZZER_NOTE_REST,
+            BUZZER_NOTE_A4,
+            BUZZER_NOTE_E5,
+            BUZZER_NOTE_REST,
+            BUZZER_NOTE_A4,
+            BUZZER_NOTE_F5,
+            BUZZER_NOTE_G5,
+            BUZZER_NOTE_E5,
+            BUZZER_NOTE_REST,
+            BUZZER_NOTE_A4,
+            BUZZER_NOTE_G5,
+            BUZZER_NOTE_F5,
+            BUZZER_NOTE_E5,
+            BUZZER_NOTE_D5,
+            BUZZER_NOTE_E5,
+            BUZZER_NOTE_REST,
+
+            BUZZER_NOTE_A5,
+            BUZZER_NOTE_REST,
+            BUZZER_NOTE_A5,
+            BUZZER_NOTE_A5SHARP_B5FLAT,
+            BUZZER_NOTE_G5,
+            BUZZER_NOTE_REST,
+            BUZZER_NOTE_C5,
+            BUZZER_NOTE_A5,
+            BUZZER_NOTE_A5SHARP_B5FLAT,
+            BUZZER_NOTE_G5,
+            BUZZER_NOTE_REST,
+            BUZZER_NOTE_D5,
+            BUZZER_NOTE_A5SHARP_B5FLAT,
+            BUZZER_NOTE_A5,
+            BUZZER_NOTE_G5,
+            BUZZER_NOTE_F5,
+            BUZZER_NOTE_E5,
+        };
+        const uint16_t durations[] = {
+            200,
+            600,
+            100,
+            200,
+            600,
+            100,
+            200,
+            400,
+            400,
+            600,
+            100,
+            200,
+            400,
+            400,
+            400,
+            400,
+            800,
+            600,
+
+            200,
+            50,
+            400,
+            200,
+            400,
+            100,
+            200,
+            400,
+            400,
+            400,
+            200,
+            200,
+            400,
+            400,
+            400,
+            400,
+            900,
+        };
+        application_state.play = false;
+        for(size_t i = 0; i < sizeof(rains); i++) {
+            char buf[9] = {0};
+            if (rains[i] == BUZZER_NOTE_REST) {
+                sprintf(buf, "%2drESt  ", i);
+            } else {
+                sprintf(buf, "%2d%6d", i, NotePeriods[rains[i]]);
+            }
+            watch_display_string(buf, 2);
+            watch_buzzer_play_note(rains[i], durations[i]);
+        }
+    }
+
+    // Wait a moment to debounce button input
+    delay_ms(250);
+    application_state.debounce_wait = false;
+
+    return true;
+}
diff --git a/Sensor Watch Buzzer Demo/make/.gitignore b/Sensor Watch Buzzer Demo/make/.gitignore
new file mode 100755
index 00000000..3722ac63
--- /dev/null
+++ b/Sensor Watch Buzzer Demo/make/.gitignore
@@ -0,0 +1 @@
+build/

diff --git a/Sensor Watch Buzzer Demo/make/Makefile b/Sensor Watch Buzzer Demo/make/Makefile
new file mode 100755
index 00000000..9b8d25c0
--- /dev/null
+++ b/Sensor Watch Buzzer Demo/make/Makefile
@@ -0,0 +1,151 @@
+##############################################################################
+BUILD = build
+BIN = watch
+
+##############################################################################
+.PHONY: all directory clean size
+
+CC = arm-none-eabi-gcc
+OBJCOPY = arm-none-eabi-objcopy
+SIZE = arm-none-eabi-size
+UF2 = python ../../utils/uf2conv.py
+
+ifeq ($(OS), Windows_NT)
+  MKDIR = gmkdir
+else
+  MKDIR = mkdir
+endif
+
+CFLAGS += -W -Wall --std=gnu99 -Os
+CFLAGS += -fno-diagnostics-show-caret
+CFLAGS += -fdata-sections -ffunction-sections
+CFLAGS += -funsigned-char -funsigned-bitfields
+CFLAGS += -mcpu=cortex-m0plus -mthumb
+CFLAGS += -MD -MP -MT $(BUILD)/$(*F).o -MF $(BUILD)/$(@F).d
+
+LDFLAGS += -mcpu=cortex-m0plus -mthumb
+LDFLAGS += -Wl,--gc-sections
+LDFLAGS += -Wl,--script=../../watch-library/linker/saml22j18.ld
+
+# If you add any additional directories with headers, add them to this list, e.g.
+# ../drivers/
+INCLUDES += \
+  -I../ \
+  -I../../watch-library/include \
+  -I../../watch-library/hal/ \
+  -I../../watch-library/hal/documentation/ \
+  -I../../watch-library/hal/include/ \
+  -I../../watch-library/hal/src/ \
+  -I../../watch-library/hal/utils/ \
+  -I../../watch-library/hal/utils/include/ \
+  -I../../watch-library/hal/utils/src/ \
+  -I../../watch-library/hpl/ \
+  -I../../watch-library/hpl/adc/ \
+  -I../../watch-library/hpl/core/ \
+  -I../../watch-library/hpl/dmac/ \
+  -I../../watch-library/hpl/eic/ \
+  -I../../watch-library/hpl/gclk/ \
+  -I../../watch-library/hpl/mclk/ \
+  -I../../watch-library/hpl/osc32kctrl/ \
+  -I../../watch-library/hpl/oscctrl/ \
+  -I../../watch-library/hpl/pm/ \
+  -I../../watch-library/hpl/port/ \
+  -I../../watch-library/hpl/rtc/ \
+  -I../../watch-library/hpl/sercom/ \
+  -I../../watch-library/hpl/slcd/ \
+  -I../../watch-library/hpl/systick/ \
+  -I../../watch-library/hpl/tcc/ \
+  -I../../watch-library/hpl/tc/ \
+  -I../../watch-library/hri/ \
+  -I../../watch-library/config/ \
+  -I../../watch-library/hw/ \
+  -I../../watch-library/watch/ \
+  -I../../watch-library
+
+# If you add any additional C files to your project, add them each to this list, e.g.
+# ../drivers/st25dv.c
+SRCS += \
+  ../app.c \
+  ../../watch-library/main.c \
+  ../../watch-library/startup_saml22.c \
+  ../../watch-library/hw/driver_init.c \
+  ../../watch-library/watch/watch.c \
+  ../../watch-library/hal/src/hal_adc_sync.c \
+  ../../watch-library/hal/src/hal_atomic.c \
+  ../../watch-library/hal/src/hal_calendar.c \
+  ../../watch-library/hal/src/hal_delay.c \
+  ../../watch-library/hal/src/hal_ext_irq.c \
+  ../../watch-library/hal/src/hal_gpio.c \
+  ../../watch-library/hal/src/hal_i2c_m_sync.c \
+  ../../watch-library/hal/src/hal_init.c \
+  ../../watch-library/hal/src/hal_io.c \
+  ../../watch-library/hal/src/hal_pwm.c \
+  ../../watch-library/hal/src/hal_slcd_sync.c \
+  ../../watch-library/hal/src/hal_sleep.c \
+  ../../watch-library/hal/utils/src/utils_assert.c \
+  ../../watch-library/hal/utils/src/utils_event.c \
+  ../../watch-library/hal/utils/src/utils_list.c \
+  ../../watch-library/hal/utils/src/utils_syscalls.c \
+  ../../watch-library/hpl/adc/hpl_adc.c \
+  ../../watch-library/hpl/core/hpl_core_m0plus_base.c \
+  ../../watch-library/hpl/core/hpl_init.c \
+  ../../watch-library/hpl/dmac/hpl_dmac.c \
+  ../../watch-library/hpl/eic/hpl_eic.c \
+  ../../watch-library/hpl/gclk/hpl_gclk.c \
+  ../../watch-library/hpl/mclk/hpl_mclk.c \
+  ../../watch-library/hpl/osc32kctrl/hpl_osc32kctrl.c \
+  ../../watch-library/hpl/oscctrl/hpl_oscctrl.c \
+  ../../watch-library/hpl/pm/hpl_pm.c \
+  ../../watch-library/hpl/rtc/hpl_rtc.c \
+  ../../watch-library/hpl/sercom/hpl_sercom.c \
+  ../../watch-library/hpl/slcd/hpl_slcd.c \
+  ../../watch-library/hpl/systick/hpl_systick.c \
+  ../../watch-library/hpl/tcc/hpl_tcc.c \
+  ../../watch-library/hpl/tc/hpl_tc.c
+
+DEFINES += \
+  -D__SAML22J18A__ \
+  -DDONT_USE_CMSIS_INIT
+
+CFLAGS += $(INCLUDES) $(DEFINES)
+
+OBJS = $(addprefix $(BUILD)/, $(notdir %/$(subst .c,.o, $(SRCS))))
+
+all: directory $(BUILD)/$(BIN).elf $(BUILD)/$(BIN).hex $(BUILD)/$(BIN).bin $(BUILD)/$(BIN).uf2 size
+
+$(BUILD)/$(BIN).elf: $(OBJS)
+	@echo LD $@
+	@$(CC) $(LDFLAGS) $(OBJS) $(LIBS) -o $@
+
+$(BUILD)/$(BIN).hex: $(BUILD)/$(BIN).elf
+	@echo OBJCOPY $@
+	@$(OBJCOPY) -O ihex $^ $@
+
+$(BUILD)/$(BIN).bin: $(BUILD)/$(BIN).elf
+	@echo OBJCOPY $@
+	@$(OBJCOPY) -O binary $^ $@
+
+$(BUILD)/$(BIN).uf2: $(BUILD)/$(BIN).bin
+	@echo UF2CONV $@
+	@$(UF2) $^ -co $@
+
+install:
+	@$(UF2) -D $(BUILD)/$(BIN).uf2
+
+%.o:
+	@echo CC $@
+	@$(CC) $(CFLAGS) $(filter %/$(subst .o,.c,$(notdir $@)), $(SRCS)) -c -o $@
+
+directory:
+	@$(MKDIR) -p $(BUILD)
+
+size: $(BUILD)/$(BIN).elf
+	@echo size:
+	@$(SIZE) -t $^
+
+clean:
+	@echo clean
+	@-rm -rf $(BUILD)
+
+-include $(wildcard $(BUILD)/*.d)
+
diff --git a/watch-library/config/peripheral_clk_config.h b/watch-library/config/peripheral_clk_config.h
index 1dec8b5e..61619b6a 100644
--- a/watch-library/config/peripheral_clk_config.h
+++ b/watch-library/config/peripheral_clk_config.h
@@ -173,7 +173,7 @@
 
 // <i> Select the clock source for TCC.
 #ifndef CONF_GCLK_TCC0_SRC
-#define CONF_GCLK_TCC0_SRC GCLK_PCHCTRL_GEN_GCLK3_Val
+#define CONF_GCLK_TCC0_SRC GCLK_PCHCTRL_GEN_GCLK0_Val
 #endif
 
 /**
@@ -181,7 +181,7 @@
  * \brief TCC0's Clock frequency
  */
 #ifndef CONF_GCLK_TCC0_FREQUENCY
-#define CONF_GCLK_TCC0_FREQUENCY 32768
+#define CONF_GCLK_TCC0_FREQUENCY 16000000
 #endif
 
 #include <hpl_osc32kctrl_config.h>
diff --git a/watch-library/watch/notes.h b/watch-library/watch/notes.h
new file mode 100644
index 00000000..95f2abbf
--- /dev/null
+++ b/watch-library/watch/notes.h
@@ -0,0 +1,114 @@
+////< @file notes.h
+
+/// @brief 108 notes for use with watch_buzzer_play_note
+typedef enum BuzzerNote {
+    BUZZER_NOTE_C0 = 0,          ///< 16.35 Hz
+    BUZZER_NOTE_C0SHARP_D0FLAT,  ///< 17.32 Hz
+    BUZZER_NOTE_D0,              ///< 18.35 Hz
+    BUZZER_NOTE_D0SHARP_E0FLAT,  ///< 19.45 Hz
+    BUZZER_NOTE_E0,              ///< 20.60 Hz
+    BUZZER_NOTE_F0,              ///< 21.83 Hz
+    BUZZER_NOTE_F0SHARP_G0FLAT,  ///< 23.12 Hz
+    BUZZER_NOTE_G0,              ///< 24.50 Hz
+    BUZZER_NOTE_G0SHARP_A0FLAT,  ///< 25.96 Hz
+    BUZZER_NOTE_A0,              ///< 27.50 Hz
+    BUZZER_NOTE_A0SHARP_B0FLAT,  ///< 29.14 Hz
+    BUZZER_NOTE_B0,              ///< 30.87 Hz
+    BUZZER_NOTE_C1,              ///< 32.70 Hz
+    BUZZER_NOTE_C1SHARP_D1FLAT,  ///< 34.65 Hz
+    BUZZER_NOTE_D1,              ///< 36.71 Hz
+    BUZZER_NOTE_D1SHARP_E1FLAT,  ///< 38.89 Hz
+    BUZZER_NOTE_E1,              ///< 41.20 Hz
+    BUZZER_NOTE_F1,              ///< 43.65 Hz
+    BUZZER_NOTE_F1SHARP_G1FLAT,  ///< 46.25 Hz
+    BUZZER_NOTE_G1,              ///< 49.00 Hz
+    BUZZER_NOTE_G1SHARP_A1FLAT,  ///< 51.91 Hz
+    BUZZER_NOTE_A1,              ///< 55.00 Hz
+    BUZZER_NOTE_A1SHARP_B1FLAT,  ///< 58.27 Hz
+    BUZZER_NOTE_B1,              ///< 61.74 Hz
+    BUZZER_NOTE_C2,              ///< 65.41 Hz
+    BUZZER_NOTE_C2SHARP_D2FLAT,  ///< 69.30 Hz
+    BUZZER_NOTE_D2,              ///< 73.42 Hz
+    BUZZER_NOTE_D2SHARP_E2FLAT,  ///< 77.78 Hz
+    BUZZER_NOTE_E2,              ///< 82.41 Hz
+    BUZZER_NOTE_F2,              ///< 87.31 Hz
+    BUZZER_NOTE_F2SHARP_G2FLAT,  ///< 92.50 Hz
+    BUZZER_NOTE_G2,              ///< 98.00 Hz
+    BUZZER_NOTE_G2SHARP_A2FLAT,  ///< 103.83 Hz
+    BUZZER_NOTE_A2,              ///< 110.00 Hz
+    BUZZER_NOTE_A2SHARP_B2FLAT,  ///< 116.54 Hz
+    BUZZER_NOTE_B2,              ///< 123.47 Hz
+    BUZZER_NOTE_C3,              ///< 130.81 Hz
+    BUZZER_NOTE_C3SHARP_D3FLAT,  ///< 138.59 Hz
+    BUZZER_NOTE_D3,              ///< 146.83 Hz
+    BUZZER_NOTE_D3SHARP_E3FLAT,  ///< 155.56 Hz
+    BUZZER_NOTE_E3,              ///< 164.81 Hz
+    BUZZER_NOTE_F3,              ///< 174.61 Hz
+    BUZZER_NOTE_F3SHARP_G3FLAT,  ///< 185.00 Hz
+    BUZZER_NOTE_G3,              ///< 196.00 Hz
+    BUZZER_NOTE_G3SHARP_A3FLAT,  ///< 207.65 Hz
+    BUZZER_NOTE_A3,              ///< 220.00 Hz
+    BUZZER_NOTE_A3SHARP_B3FLAT,  ///< 233.08 Hz
+    BUZZER_NOTE_B3,              ///< 246.94 Hz
+    BUZZER_NOTE_C4,              ///< 261.63 Hz
+    BUZZER_NOTE_C4SHARP_D4FLAT,  ///< 277.18 Hz
+    BUZZER_NOTE_D4,              ///< 293.66 Hz
+    BUZZER_NOTE_D4SHARP_E4FLAT,  ///< 311.13 Hz
+    BUZZER_NOTE_E4,              ///< 329.63 Hz
+    BUZZER_NOTE_F4,              ///< 349.23 Hz
+    BUZZER_NOTE_F4SHARP_G4FLAT,  ///< 369.99 Hz
+    BUZZER_NOTE_G4,              ///< 392.00 Hz
+    BUZZER_NOTE_G4SHARP_A4FLAT,  ///< 415.30 Hz
+    BUZZER_NOTE_A4,              ///< 440.00 Hz
+    BUZZER_NOTE_A4SHARP_B4FLAT,  ///< 466.16 Hz
+    BUZZER_NOTE_B4,              ///< 493.88 Hz
+    BUZZER_NOTE_C5,              ///< 523.25 Hz
+    BUZZER_NOTE_C5SHARP_D5FLAT,  ///< 554.37 Hz
+    BUZZER_NOTE_D5,              ///< 587.33 Hz
+    BUZZER_NOTE_D5SHARP_E5FLAT,  ///< 622.25 Hz
+    BUZZER_NOTE_E5,              ///< 659.25 Hz
+    BUZZER_NOTE_F5,              ///< 698.46 Hz
+    BUZZER_NOTE_F5SHARP_G5FLAT,  ///< 739.99 Hz
+    BUZZER_NOTE_G5,              ///< 783.99 Hz
+    BUZZER_NOTE_G5SHARP_A5FLAT,  ///< 830.61 Hz
+    BUZZER_NOTE_A5,              ///< 880.00 Hz
+    BUZZER_NOTE_A5SHARP_B5FLAT,  ///< 932.33 Hz
+    BUZZER_NOTE_B5,              ///< 987.77 Hz
+    BUZZER_NOTE_C6,              ///< 1046.50 Hz
+    BUZZER_NOTE_C6SHARP_D6FLAT,  ///< 1108.73 Hz
+    BUZZER_NOTE_D6,              ///< 1174.66 Hz
+    BUZZER_NOTE_D6SHARP_E6FLAT,  ///< 1244.51 Hz
+    BUZZER_NOTE_E6,              ///< 1318.51 Hz
+    BUZZER_NOTE_F6,              ///< 1396.91 Hz
+    BUZZER_NOTE_F6SHARP_G6FLAT,  ///< 1479.98 Hz
+    BUZZER_NOTE_G6,              ///< 1567.98 Hz
+    BUZZER_NOTE_G6SHARP_A6FLAT,  ///< 1661.22 Hz
+    BUZZER_NOTE_A6,              ///< 1760.00 Hz
+    BUZZER_NOTE_A6SHARP_B6FLAT,  ///< 1864.66 Hz
+    BUZZER_NOTE_B6,              ///< 1975.53 Hz
+    BUZZER_NOTE_C7,              ///< 2093.00 Hz
+    BUZZER_NOTE_C7SHARP_D7FLAT,  ///< 2217.46 Hz
+    BUZZER_NOTE_D7,              ///< 2349.32 Hz
+    BUZZER_NOTE_D7SHARP_E7FLAT,  ///< 2489.02 Hz
+    BUZZER_NOTE_E7,              ///< 2637.02 Hz
+    BUZZER_NOTE_F7,              ///< 2793.83 Hz
+    BUZZER_NOTE_F7SHARP_G7FLAT,  ///< 2959.96 Hz
+    BUZZER_NOTE_G7,              ///< 3135.96 Hz
+    BUZZER_NOTE_G7SHARP_A7FLAT,  ///< 3322.44 Hz
+    BUZZER_NOTE_A7,              ///< 3520.00 Hz
+    BUZZER_NOTE_A7SHARP_B7FLAT,  ///< 3729.31 Hz
+    BUZZER_NOTE_B7,              ///< 3951.07 Hz
+    BUZZER_NOTE_C8,              ///< 4186.01 Hz
+    BUZZER_NOTE_C8SHARP_D8FLAT,  ///< 4434.92 Hz
+    BUZZER_NOTE_D8,              ///< 4698.63 Hz
+    BUZZER_NOTE_D8SHARP_E8FLAT,  ///< 4978.03 Hz
+    BUZZER_NOTE_E8,              ///< 5274.04 Hz
+    BUZZER_NOTE_F8,              ///< 5587.65 Hz
+    BUZZER_NOTE_F8SHARP_G8FLAT,  ///< 5919.91 Hz
+    BUZZER_NOTE_G8,              ///< 6271.93 Hz
+    BUZZER_NOTE_G8SHARP_A8FLAT,  ///< 6644.88 Hz
+    BUZZER_NOTE_A8,              ///< 7040.00 Hz
+    BUZZER_NOTE_A8SHARP_B8FLAT,  ///< 7458.62 Hz
+    BUZZER_NOTE_B8,              ///< 7902.13 Hz
+    BUZZER_NOTE_REST             ///< no sound
+} BuzzerNote;
diff --git a/watch-library/watch/watch.c b/watch-library/watch/watch.c
index 170c4747..d3e32d5c 100644
--- a/watch-library/watch/watch.c
+++ b/watch-library/watch/watch.c
@@ -172,6 +172,9 @@ inline void watch_clear_pixel(uint8_t com, uint8_t seg) {
 }
 
 void watch_display_character(uint8_t character, uint8_t position) {
+    // handle lowercase 7 if needed
+    if (character == '7' && (position == 4 || position == 6)) character = '&';
+
     uint64_t segmap = Segment_Map[position];
     uint64_t segdata = Character_Set[character - 0x20];
 
@@ -319,6 +322,39 @@ void watch_set_led_off() {
     }
 }
 
+
+//////////////////////////////////////////////////////////////////////////////////////////
+// Buzzer
+
+inline void watch_enable_buzzer() {
+    PWM_1_init();
+}
+
+inline void watch_set_buzzer_period(uint32_t period) {
+    pwm_set_parameters(&PWM_1, period, period / 2);
+}
+
+inline void watch_set_buzzer_on() {
+	pwm_enable(&PWM_1);
+}
+
+inline void watch_set_buzzer_off() {
+	pwm_disable(&PWM_1);
+}
+
+const uint16_t NotePeriods[108] = {31047, 29301, 27649, 26079, 24617, 23224, 21923, 20683, 19515, 18418, 17377, 16399, 15477, 14603, 13780, 13004, 12272, 11580, 10926, 10311, 9730, 9181, 8664, 8175, 7714, 7280, 6869, 6483, 6117, 5772, 5447, 5140, 4850, 4577, 4319, 4076, 3846, 3629, 3425, 3232, 3050, 2878, 2715, 2562, 2418, 2282, 2153, 2032, 1917, 1809, 1707, 1611, 1520, 1435, 1354, 1277, 1205, 1137, 1073, 1013, 956, 902, 851, 803, 758, 715, 675, 637, 601, 567, 535, 505, 476, 450, 424, 400, 378, 357, 336, 317, 300, 283, 267, 252, 238, 224, 212, 200, 188, 178, 168, 158, 149, 141, 133, 125, 118, 112, 105, 99, 94, 89, 84, 79, 74, 70, 66, 63};
+
+void watch_buzzer_play_note(BuzzerNote note, uint16_t duration_ms) {
+    if (note == BUZZER_NOTE_REST) {
+        watch_set_buzzer_off();
+    } else {
+        pwm_set_parameters(&PWM_1, NotePeriods[note], NotePeriods[note] / 2);
+        watch_set_buzzer_on();
+    }
+    delay_ms(duration_ms);
+    watch_set_buzzer_off();
+}
+
 //////////////////////////////////////////////////////////////////////////////////////////
 // Real-time Clock
 
diff --git a/watch-library/watch/watch.h b/watch-library/watch/watch.h
index 43f582a3..66a0cc27 100644
--- a/watch-library/watch/watch.h
+++ b/watch-library/watch/watch.h
@@ -6,6 +6,7 @@
 #include "driver_init.h"
 #include "hpl_calendar.h"
 #include "hal_ext_irq.h"
+#include "notes.h"
 
 /** @mainpage Sensor Watch Documentation
  *  @brief This documentation covers most of the functions you will use to interact with the Sensor Watch
@@ -14,12 +15,13 @@
                          Sensor Watch app.
             - @ref slcd - This section covers functions related to the Segment LCD display driver, which is responsible
                           for displaying strings of characters and indicators on the main watch display.
+            - @ref buttons - This section covers functions related to the three buttons: Light, Mode and Alarm.
             - @ref led - This section covers functions related to the bi-color red/green LED mounted behind the LCD.
+            - @ref buzzer - This section covers functions related to the piezo buzzer.
             - @ref rtc - This section covers functions related to the SAM L22's real-time clock peripheral, including
                          date, time and alarm functions.
             - @ref adc - This section covers functions related to the SAM L22's analog-to-digital converter, as well as
                          configuring and reading values from the three analog-capable pins on the 9-pin connector.
-            - @ref buttons - This section covers functions related to the three buttons: Light, Mode and Alarm.
             - @ref gpio - This section covers functions related to general-purpose input and output signals.
             - @ref i2c - This section covers functions related to the SAM L22's built-I2C driver, including configuring
                          the I2C bus, putting values directly on the bus and reading data from registers on I2C devices.
@@ -215,6 +217,45 @@ void watch_set_led_off();
 /// @}
 
 
+/** @addtogroup buzzer Buzzer
+  * @brief This section covers functions related to the piezo buzzer embedded in the F-91W's back plate.
+  */
+/// @{
+/** @brief Enables the TCC peripheral, which drives the buzzer.
+  */
+void watch_enable_buzzer();
+
+/** @brief Sets the period of the buzzer.
+  * @param period The period of a single cycle for the PWM peripheral. You can use the following formula to
+  *               convert a desired frequency to a period for this function: period = 513751 * (freq^−1.0043)
+  */
+void watch_set_buzzer_period(uint32_t period);
+
+/** @brief Turns the buzzer output on. It will emit a continuous sound at the given frequency.
+  * @note The TCC peripheral that drives the buzzer does not run in standby mode; if you wish for buzzer
+  *       output to continue, you should prevent your app from going to sleep.
+  */
+void watch_set_buzzer_on();
+
+/** @brief Turns the buzzer output off.
+  */
+void watch_set_buzzer_off();
+
+/** @brief Plays the given note for a set duration.
+  * @param note The note you wish to play, or BUZZER_NOTE_REST to disable output for the given duration.
+  * @param duration_ms The duration of the note.
+  * @note Note that this will block your UI for the duration of the note's play time, and it will
+  *       after this call, the buzzer period will be set to the period of this note.
+  */
+void watch_buzzer_play_note(BuzzerNote note, uint16_t duration_ms);
+
+/** @brief An array of periods for all the notes on a piano, corresponding to the names in BuzzerNote.
+  */
+extern const uint16_t NotePeriods[108];
+
+/// @}
+
+
 /** @addtogroup rtc Real-Time Clock
   * @brief This section covers functions related to the SAM L22's real-time clock peripheral, including
   *        date, time and alarm functions.