Exiting Sleep, and reset questions.

XBee & XBee Gateway XBee - 802.15.4
1

I’m using Series 1 in non API mode and seeking information apparently not in the XBee data sheet. I have two XBees that are communicating on lab boards, so I know they work. I am developing another board in which I do not yet have total functionality, but the module does draw low current on power up in sleep mode, and also draws the much higher ~ 50 mA when ‘exiting’ sleep. Here are my questions regarding this new application:

  1. I am initially powering up the XBee module with pin 9 (SM=1) high because my application is then coin-cell battery powered, and only later will alternate power become available with enough current to power the XBee @ 3.5V. Once this power becomes available and I set pin 9 low to wake up the XBee, will it then be functional, or is a reset pulse required after waking the part the first time after power-up for it to be reliably functional (since it was initially powered up in sleep mode)? Or, is there a problem powering up the module in the sleep mode in the first place?

  2. How long after the required 200 nSec reset pulse is applied, then removed, until the module is ready to xmit/receive. i.e., how long does the reset process take to complete? I hope it’s < 100 mSec, and preferably closer to 10 mSec.

I can run some tests to obtain answers to these questions but would like to confirm them from an authoritative source (i.e. Digi Apps. Support, if possible). I also suggest the answers to these questions be included in the data sheet since other users will need this information in the future.

Thanks in advance for any assistance.

Odessa

2

My testing so far reveals that if I power up the XBee with pin 9 hi (asserting sleep), then later set that pin low, the XBee will not operate properly without first issuing a reset after exiting sleep the first time. Anybody at Digi confirm this to be expected? I need to know this for production runs with moderately high volumes, so I don’t want to base my conclusion exclusively on minimal testing here.

So, now that it appears a reset is required after exiting sleep the first time after power-up, how long after the end of the reset pulse will the XBee be ready to transceive?

Thanks, Odessa

3

You should not need to issue a reset - I’ve never heard of that being required. You could send an email to supportwizards@digi.com and ask.

I think the problem is some other setting in either your local node or teh remotes, but i am not an 802.15.4 expert.

4

Thanks, Lynnl, I’ll check at the email address you listed.

Odessa