Add BME280 temperature display on timer ISR

metronom.ino

@@ -1,3 +1,15 @@
+#include "SAMDTimerInterrupt.h"
+#include "SAMD_ISR_Timer.h"
+
+#define HW_TIMER_INTERVAL_MS 10
+SAMDTimer ITimer(TIMER_TC3);
+SAMD_ISR_Timer ISR_Timer;
+
+void TimerHandler(void) {
+  ISR_Timer.run();
+}
+
+
 const uint BUZZER_PIN = 0;
 
 const uint BUTTON_LED_PIN = 5;
@@ -14,6 +26,10 @@ void setup() {
   // Order of ISRs matter: RISING should be invoked first
   attachInterrupt(digitalPinToInterrupt(BUTTON_PIN), buttonISRtime, CHANGE);
   attachInterrupt(digitalPinToInterrupt(BUTTON_PIN), buttonISRstate, RISING);
+
+  initTemperature();
+  ITimer.attachInterruptInterval_MS(10, TimerHandler);
+  ISR_Timer.setInterval(1000, readTemperature);
 }
 
 void loop() {

temperature.ino

@@ -0,0 +1,21 @@
+#include "grove_alphanumeric_display.h"
+#include "Seeed_BME280.h"
+
+Seeed_Digital_Tube tube;
+BME280 sensor;
+
+void initTemperature() {
+  // BME280 inits Wire
+  sensor.init();
+  
+  tube.setTubeType(TYPE_4, TYPE_4_DEFAULT_I2C_ADDR);
+  tube.setBrightness(15);
+  tube.setBlinkRate(BLINK_OFF);
+  tube.setPoint(true,true);
+}
+
+void readTemperature() {
+  char temperature_str[5];
+  sprintf(temperature_str, "%4u", (unsigned int) (sensor.getTemperature() * 100.0));
+  tube.displayString(temperature_str);
+}