I’m running an XBee in sleep mode 2 (doze mode) and waking it up a couple of times a second for about 10ms using the wake pin. About half of the time it works perfectly, the rest of the time it just won’t sleep. This shows the wake pin (blue line) and the status pin (yellow line):
The wake pin gets is pulled low every time (ignore the slightly longer wakeful period about 80% of the way through) and the xbee wakes up, but when the wake pin goes high it doesn’t always go back to sleep again, seemingly at random.
Has anybody got any ideas?
Please identify the XBee model and firmware revision being used. There is a bug report associated with the XBee S2C SMT firmware which sounds like what you are seeing. If so, there is a fix for it in an upcoming release.
Looks like it’s an XBee Pro S1 (model: XBPRO) and the firmware version is 10EC.
Is there a workaround for this or any more precise details about what causes it? We’ve got some of these out in the field and we’re not sensibly going to be able to update the XBee firmware.
Sounds like you are not keeping the radio awake long enough to process the data request. What happens if you keep the module awake for 20 - 30ms?
I think we’ve found the problem - we were pulling the tx line low immediately after putting the xbee to sleep.
I’m guessing this led to a race condition to see whether the xbee would manage to go to sleep before it sees the tx line and decides to wait up and see if there’s a message for it.
Thanks Robert for all your help,