The current implementation is obviously broken and I think it should be fixed using (optimized) compiler-agnostic asm code. This should fix the backwards-compatibility problem. In a long term view it ...
#define PULSE_PIN 3 void setup() { Serial.begin(115200); pinMode(PULSE_PIN, INPUT_PULLUP); uint32_t pulse = pulseIn(PULSE_PIN, HIGH, 6000); Serial.print ("pulse len ...