Skip audio output if DAC not attached

src/boot_animation.py

@@ -20,6 +20,16 @@ display = supervisor.runtime.display
 display.auto_refresh = False
 
 i2c = board.I2C()
+# Check if DAC is connected
+while not i2c.try_lock():
+    time.sleep(0.01)
+if 0x18 in i2c.scan():
+    ltv320_present = True
+else:
+    ltv320_present = False
+i2c.unlock()
+
+if ltv320_present:
     dac = adafruit_tlv320.TLV320DAC3100(i2c)
 
     # set sample rate & bit depth
@@ -621,6 +631,7 @@ display.root_group = main_group
 
 start_time = time.monotonic()
 
+if ltv320_present:
     audio.play(wave)
 
 while True:
@@ -668,6 +679,7 @@ while True:
     if not still_going:
         break
 
+if ltv320_present:
     while audio.playing:
         pass