Merge pull request #307 from FrankBoesing/patch-1

Add delayNanoseconds()

teensy4/core_pins.h

 	while (ARM_DWT_CYCCNT - begin < cycles) ; // wait
 }
 
+static inline void delayNanoseconds(uint32_t) __attribute__((always_inline, unused));
+static inline void delayNanoseconds(uint32_t nsec)
+{
+	uint32_t begin = ARM_DWT_CYCCNT;
+	uint32_t cycles =  ((uint64_t)F_CPU_ACTUAL * nsec) / 1000000000UL;
+	while (ARM_DWT_CYCCNT - begin < cycles) ; // wait
+}
 
 
 unsigned long rtc_get(void);