Got some serial garbage coming out my FIO XBee, as soon as I wake up the XBee. The actual message being sent after that comes in fine though. This is what happens: 1- XBee slows (Pin Hibernate) 2- Arduino sleeps (Watchdog, power down) 3- After X times watchdog interrupts, the main cycle will wake up the XBee 4- When the XBee wakes up (pin output gets low), it sends something like ~.....)...... to another XBee, connected to the PC and monitored by X-CTU 6- ~2 seconds later the Arduino sends the actual message, will be received fine. 7- XBee is put asleep again (no garbage coming after the message or on shutdown btw) 8- Arduino puts itself asleep again
This does NOT happen when the I disable the "Pin Hibernate" sleep modus on the Xbee. Anyway, I tried to flush the Serial when waking up and just before putting the XBee asleep, but it still happens. I must also say that the garbage content isn't completely random. The length and the characters are almost the same each time.
Another little test. When I send no messages at all (no Serial.print), the same garbabe still occurs. Again, with sleepmodus disabled the clean stays clean though.
I guess waking up triggers some electro magic. I've read short bits about catching that with a resistor or something, but ifso, could someone give a bit more details about how to fix that on a FIO + XBee, using sleep and a battery?
Further details: XBee Pro Series 1 Arduino FIO Powered by a battery 3x2000 mAh, 3.7V 7.40Wh * I don't have an extra USB cable to check if it still happens without the battery...