add TCC beep example

examples/beep_tcc/Makefile

@@ -0,0 +1,15 @@
+# Keep this first line.
+GOSSAMER_PATH = ../..
+
+# If your firmware targets a specific board, specify it here,
+# or omit it and provide it on the command line (make BOARD=foo).
+BOARD=circuitplayground
+
+# Leave this line here.
+include $(GOSSAMER_PATH)/make.mk
+
+SRCS += \
+  ./app.c \
+
+# Finally, leave this line at the bottom of the file.
+include $(GOSSAMER_PATH)/rules.mk

examples/beep_tcc/app.c

@@ -0,0 +1,22 @@
+#include "app.h"
+#include "delay.h"
+#include "tcc.h"
+
+void app_init(void) {
+}
+
+void app_setup(void) {
+    HAL_GPIO_A1_out();
+    HAL_GPIO_A1_pmuxen(HAL_GPIO_PMUX_TC_TCC);
+
+    // 8 Mhz / 250 = 32 kHz
+    tcc_init(0, GENERIC_CLOCK_0, TCC_PRESCALER_DIV1);
+    tcc_set_wavegen(0, TCC_WAVEGEN_NORMAL_PWM);
+    tcc_set_period(0, 250, false);
+    tcc_set_cc(0, 1, 125, false);
+    tcc_enable(0);
+}
+
+bool app_loop(void) {
+    return false;
+}