feat: Add basic watchdog timer

Signed-off-by: Matthias Blankertz <matthias@blankertz.org>

software/src/main.py

@@ -53,6 +53,13 @@ def setup_wifi():
     print(f"ifconfig: {wlan.ifconfig()}")
 
 
+async def wdt_task(wdt):
+    # TODO: more checking of app health
+    # Right now this only protects against the asyncio executor crashing completely
+    while True:
+        await asyncio.sleep_ms(500)
+        wdt.feed()
+
 DB_PATH = '/sd/tonberry.db'
 
 config = Configuration()
@@ -97,8 +104,10 @@ def run():
 
             start_webserver(config, the_app)
             # Start
+            wdt = machine.WDT(timeout=1000)
             asyncio.create_task(aiorepl.task({'timer_manager': TimerManager(),
                                               'app': the_app}))
+            asyncio.create_task(wdt_task(wdt))
             asyncio.get_event_loop().run_forever()