big PWM refactor: drive both LEDs and buzzer from TCC

1 files changed, 16 insertions, 6 deletions

diff --git a/watch-library/watch/watch_buzzer.c b/watch-library/watch/watch_buzzer.c
index 72771508..c6c89a0e 100644
--- a/watch-library/watch/watch_buzzer.c
+++ b/watch-library/watch/watch_buzzer.c
@@ -23,28 +23,38 @@
  */
 
  inline void watch_enable_buzzer() {
-    PWM_1_init();
+    if (!hri_tcc_get_CTRLA_reg(TCC0, TCC_CTRLA_ENABLE)) {
+        _watch_enable_tcc();
+    }
 }
-
 inline void watch_set_buzzer_period(uint32_t period) {
-    pwm_set_parameters(&PWM_1, period, period / 2);
+    hri_tcc_write_PERBUF_reg(TCC0, period);
+}
+
+void watch_disable_buzzer() {
+    _watch_disable_tcc();
 }
 
 inline void watch_set_buzzer_on() {
-	pwm_enable(&PWM_1);
+    gpio_set_pin_direction(BUZZER, GPIO_DIRECTION_OUT);
+    gpio_set_pin_function(BUZZER, PINMUX_PA27F_TCC0_WO5);
 }
 
 inline void watch_set_buzzer_off() {
-	pwm_disable(&PWM_1);
+    gpio_set_pin_direction(BUZZER, GPIO_DIRECTION_OFF);
+    gpio_set_pin_function(BUZZER, GPIO_PIN_FUNCTION_OFF);
 }
 
+// note: the buzzer uses a 1 MHz clock. these values were determined by dividing 1,000,000 by the target frequency.
+// i.e. for a 440 Hz tone (A4 on the piano), 1MHz/440Hz = 2273
 const uint16_t NotePeriods[108] = {18182,17161,16197,15288,14430,13620,12857,12134,11453,10811,10204,9631,9091,8581,8099,7645,7216,6811,6428,6068,5727,5405,5102,4816,4545,4290,4050,3822,3608,3405,3214,3034,2863,2703,2551,2408,2273,2145,2025,1911,1804,1703,1607,1517,1432,1351,1276,1204,1136,1073,1012,956,902,851,804,758,716,676,638,602,568,536,506,478,451,426,402,379,358,338,319,301,284,268,253,239,225,213,201,190,179,169,159,150,142,134,127};
 
 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);
+        hri_tcc_write_PERBUF_reg(TCC0, NotePeriods[note]);
+        hri_tcc_write_CCBUF_reg(TCC0, 1, NotePeriods[note] / 2);
         watch_set_buzzer_on();
     }
     delay_ms(duration_ms);