Fix AudioProcessorUsage() on Teensy LC

teensy3/AudioStream.cpp

 {
 	AudioStream *p;
 
+#if defined(KINETISK)
 	ARM_DEMCR |= ARM_DEMCR_TRCENA;
 	ARM_DWT_CTRL |= ARM_DWT_CTRL_CYCCNTENA;
 	uint32_t totalcycles = ARM_DWT_CYCCNT;
+#elif defined(KINETISL)
+	uint32_t totalcycles = micros();
+#endif
 	//digitalWriteFast(2, HIGH);
 	for (p = AudioStream::first_update; p; p = p->next_update) {
 		if (p->active) {
 		}
 	}
 	//digitalWriteFast(2, LOW);
-	totalcycles = (ARM_DWT_CYCCNT - totalcycles) >> 4;;
+#if defined(KINETISK)
+	totalcycles = (ARM_DWT_CYCCNT - totalcycles) >> 4;
+#elif defined(KINETISL)
+	totalcycles = micros() - totalcycles;
+#endif
 	AudioStream::cpu_cycles_total = totalcycles;
 	if (totalcycles > AudioStream::cpu_cycles_total_max)
 		AudioStream::cpu_cycles_total_max = totalcycles;

teensy3/AudioStream.h

 	AudioStream::initialize_memory(data, num); \
 })
 
+#if defined(KINETISK)
 #define CYCLE_COUNTER_APPROX_PERCENT(n) (((n) + (F_CPU / 32 / AUDIO_SAMPLE_RATE * AUDIO_BLOCK_SAMPLES / 100)) / (F_CPU / 16 / AUDIO_SAMPLE_RATE * AUDIO_BLOCK_SAMPLES / 100))
+#elif defined(KINETISL)
+#define CYCLE_COUNTER_APPROX_PERCENT(n) ((n) * (int)(AUDIO_SAMPLE_RATE) + (int)(AUDIO_SAMPLE_RATE/2)) / (AUDIO_BLOCK_SAMPLES * 10000)
+#endif
 
 #define AudioProcessorUsage() (CYCLE_COUNTER_APPROX_PERCENT(AudioStream::cpu_cycles_total))
 #define AudioProcessorUsageMax() (CYCLE_COUNTER_APPROX_PERCENT(AudioStream::cpu_cycles_total_max))