Entering Command mode in cylic sleep mode

XBee & XBee Gateway XBee - Point-to-Point/Multi-Point
1

Shalom!

  1. I am trying to configure the XSC by way of my embedded micro-controller after power up. There were no problems doing this until we needed to also implement cyclic sleep mode to save power in the remote XSC units.
    Now I am having trouble entering command mode. I wait for the XSC’s CTS* line to go low and send a “+++” sequence and wait another second before sending the first AT command. This does not seem to work as I get no response.
    We could setup the XSCs using the prototype development board but since we may want to change RF Destination addresses it would complicate deployment.
    Our remote units will send a status message once a minute to a “Master” XSC unit. I wanted also to get the remote or "Slave’ units to go back to sleep as soon as possible, so I thought to reduce the “ST” to 3 seconds. The Master may infrequently send commands and requests from the remotes.

Here are the commands I send:

const char *XBEE_CMD[XBEE_NUM_INIT_CMDS] =
{“ATID”, // ID VendorID
“ATDT”, // Destination Address
“ATHP2\r”, // Hop Table 2
“ATST100\r”, // Time Before Sleep 10 sec
“ATLH82\r”, // Wakeup Init timer 8.2s
“ATSM7\r”, // Sleep Mode 8s cyclic sleep
“ATWR\r”, // Write to save
“ATSL\r”, // Read LSW Serial Number
“ATSH\r”, // Read MSW Serial Number
“ATCN\r” // Exit Command Mode
};

  1. Retries
    Since we will sometimes use two remotes and they are not synchronized, there could be a collision if both sent status (once a minute) at the same time. In the pdf it seems like that retries are not encouraged. Should I just set the “RR” to 1. Since this will enable acks won’t it cause more current consumption?
    Do I really need to set the “RN” field too?

  2. HT
    Our Master XSC will never sleep (SM=0) but i understand that I should set its “HT” to the “slaves” “ST”.
    Can I just leave the “Slaves” HT to the default since slaves only need to talk to the non sleeping Master?

Thanks
David Kaplan